• film cap test

    From John Larkin@21:1/5 to All on Wed Jul 6 14:34:59 2022
    We want some biggish film caps to use in some LC filters for a couple
    of switching power things, so we got some to test.

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
    into the test rig with longer leads the ESL spikes go way up,
    consistent with the loop area, so the low ESL seems real. It will be
    even lower soldered on a PCB, into some hunky copper planes.

    Of course ESL is not a lumped property of a wound film cap, but this
    is close.

    We were considering some big ceramic caps, but they lose 80% of their
    c at our 48 volts DC.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to John Larkin on Wed Jul 6 18:33:03 2022
    John Larkin wrote:

    We want some biggish film caps to use in some LC filters for a couple
    of switching power things, so we got some to test.

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
    into the test rig with longer leads the ESL spikes go way up,
    consistent with the loop area, so the low ESL seems real. It will be
    even lower soldered on a PCB, into some hunky copper planes.

    Of course ESL is not a lumped property of a wound film cap, but this
    is close.

    We were considering some big ceramic caps, but they lose 80% of their
    c at our 48 volts DC.


    Fun! That's quite a lot lower than I would have expected, and a useful
    wrench for the toolkit.

    Of course the null position just demonstrates that some series-LC
    someplace in a more complicated model has that inductance--the external
    leads, banana jack, and so on will contribute as normal.

    That 8 nH is reasonably believable because the conduction current in
    adjacent foils goes in opposite directions and the capacitive
    displacement current will be more or less radially symmetric, so that
    the B field tends to cancel there too. (Inductance goes as the volume
    integral of |B/I|**2.)

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From whit3rd@21:1/5 to John Larkin on Wed Jul 6 18:01:22 2022
    On Wednesday, July 6, 2022 at 2:35:09 PM UTC-7, John Larkin wrote:
    We want some biggish film caps to use in some LC filters for a couple
    of switching power things, so we got some to test.

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
    into the test rig with longer leads the ESL spikes go way up,
    consistent with the loop area, so the low ESL seems real. It will be
    even lower soldered on a PCB, into some hunky copper planes.

    Of course ESL is not a lumped property of a wound film cap, but this
    is close.

    Could it be a stacked-foil item, instead? Mechanically, those have
    windings, but the leadwires contact in two spots on each layer.
    They're always radial, not axial (I think...).

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to All on Wed Jul 6 18:55:33 2022
    On Wed, 6 Jul 2022 18:01:22 -0700 (PDT), whit3rd <whit3rd@gmail.com>
    wrote:

    On Wednesday, July 6, 2022 at 2:35:09 PM UTC-7, John Larkin wrote:
    We want some biggish film caps to use in some LC filters for a couple
    of switching power things, so we got some to test.

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
    into the test rig with longer leads the ESL spikes go way up,
    consistent with the loop area, so the low ESL seems real. It will be
    even lower soldered on a PCB, into some hunky copper planes.

    Of course ESL is not a lumped property of a wound film cap, but this
    is close.

    Could it be a stacked-foil item, instead? Mechanically, those have >windings, but the leadwires contact in two spots on each layer.
    They're always radial, not axial (I think...).

    I really want a high-res xray machine. I guess I could whack this cap
    with a hammer and get an idea of the construction.

    I just tested one of these

    https://www.mouser.com/ProductDetail/XP-Power/SRH05S12?qs=w%2Fv1CP2dgqoB4ok%252BZU%252BVXg%3D%3D

    and it was remarkable. It would be cool to see what's inside.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Allison@21:1/5 to John Larkin on Wed Jul 6 19:46:27 2022
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?
    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf

    .... Phil

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Phil Allison on Thu Jul 7 10:39:39 2022
    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?
    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Thu Jul 7 07:51:24 2022
    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>
    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?

    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating
    from ripple current at 250 KHz. I'm better equipped to measure these
    things.

    I like to measure (and explode) parts. I wonder what will happen if I
    put kilovolts into this one. Any guesses?


    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the >imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.

    Cheers

    Phil Hobbs

    The conductive path, end to end, is probably many concentric cylinders
    of foil, which I guess could have very low inductance. In my
    measurement, the leads themselves seem to dominate L.

    The frequency null computes to 8 nH against the 6.8 uF capacitance.
    Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to All on Thu Jul 7 10:07:49 2022
    On Thu, 07 Jul 2022 07:51:24 -0700, jlarkin@highlandsniptechnology.com
    wrote:

    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>>
    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?

    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating
    from ripple current at 250 KHz. I'm better equipped to measure these
    things.

    I like to measure (and explode) parts. I wonder what will happen if I
    put kilovolts into this one. Any guesses?


    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the >>imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.

    Cheers

    Phil Hobbs

    The conductive path, end to end, is probably many concentric cylinders
    of foil, which I guess could have very low inductance. In my
    measurement, the leads themselves seem to dominate L.

    The frequency null computes to 8 nH against the 6.8 uF capacitance.
    Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm. But IR is still off the scale on my Fluke
    DVM and it's still a capacitor around its original value.

    https://www.dropbox.com/s/n1gp3h7h1v4bzw6/CDE_Guts.jpg?raw=1

    It appears to be a metalized film spiral that has big metal (flame
    sprayed?) electrodes on both ends.

    We'll use lots of these so it's good to understand them.


    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cydrome Leader@21:1/5 to John Larkin on Thu Jul 7 19:44:22 2022
    John Larkin <jlarkin@highland_atwork_technology.com> wrote:
    On Thu, 07 Jul 2022 07:51:24 -0700, jlarkin@highlandsniptechnology.com
    wrote:

    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs >><pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>>>
    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?

    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating
    from ripple current at 250 KHz. I'm better equipped to measure these >>things.

    I like to measure (and explode) parts. I wonder what will happen if I
    put kilovolts into this one. Any guesses?


    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the >>>imperially challenged). However, that cap is 26 mm long, not even >>>counting the banana connectors, which ought to be above 20 nH.

    Cheers

    Phil Hobbs

    The conductive path, end to end, is probably many concentric cylinders
    of foil, which I guess could have very low inductance. In my
    measurement, the leads themselves seem to dominate L.

    The frequency null computes to 8 nH against the 6.8 uF capacitance.
    Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm. But IR is still off the scale on my Fluke
    DVM and it's still a capacitor around its original value.

    https://www.dropbox.com/s/n1gp3h7h1v4bzw6/CDE_Guts.jpg?raw=1

    It appears to be a metalized film spiral that has big metal (flame
    sprayed?) electrodes on both ends.

    We'll use lots of these so it's good to understand them.



    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From legg@21:1/5 to jlarkin@highland_atwork_technology. on Thu Jul 7 15:55:04 2022
    On Thu, 07 Jul 2022 10:07:49 -0700, John Larkin <jlarkin@highland_atwork_technology.com> wrote:

    <snip>

    The frequency null computes to 8 nH against the 6.8 uF capacitance.
    Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm. But IR is still off the scale on my Fluke
    DVM and it's still a capacitor around its original value.

    https://www.dropbox.com/s/n1gp3h7h1v4bzw6/CDE_Guts.jpg?raw=1

    It appears to be a metalized film spiral that has big metal (flame
    sprayed?) electrodes on both ends.

    . . . . . called 'schoopage'.


    We'll use lots of these so it's good to understand them.

    RL

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From legg@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Thu Jul 7 15:48:50 2022
    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>
    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?
    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the >imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.

    Cheers

    Phil Hobbs

    I think the rule of thumb takes into account a return
    path for a straight wire separated by a PCB thickness.

    The test jig illustrated has terminals mounted on
    0.75 inch centers.

    If that is being 'nulled', then you'd get a different
    measurement, not the full loop.

    The rolled film cap construction has a larger width
    than a straight wire. This gives the path a reduced
    L/W ration, reducing both R and L.

    RL

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to legg on Thu Jul 7 13:29:44 2022
    On Thu, 07 Jul 2022 15:55:04 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 07 Jul 2022 10:07:49 -0700, John Larkin ><jlarkin@highland_atwork_technology.com> wrote:

    <snip>

    The frequency null computes to 8 nH against the 6.8 uF capacitance. >>>Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm. But IR is still off the scale on my Fluke
    DVM and it's still a capacitor around its original value.

    https://www.dropbox.com/s/n1gp3h7h1v4bzw6/CDE_Guts.jpg?raw=1

    It appears to be a metalized film spiral that has big metal (flame >>sprayed?) electrodes on both ends.

    . . . . . called 'schoopage'.


    We'll use lots of these so it's good to understand them.

    RL

    Maybe they manufacture them shorted and use the self-clearing effect
    to remove the shorts.

    And maybe they test them to arc-over, ditto.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to legg on Thu Jul 7 18:11:34 2022
    legg wrote:
    On Thu, 07 Jul 2022 10:07:49 -0700, John Larkin <jlarkin@highland_atwork_technology.com> wrote:

    <snip>

    The frequency null computes to 8 nH against the 6.8 uF capacitance.
    Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm. But IR is still off the scale on my Fluke
    DVM and it's still a capacitor around its original value.

    https://www.dropbox.com/s/n1gp3h7h1v4bzw6/CDE_Guts.jpg?raw=1

    It appears to be a metalized film spiral that has big metal (flame
    sprayed?) electrodes on both ends.

    . . . . . called 'schoopage'.


    We'll use lots of these so it's good to understand them.

    RL

    Fun--named after a Dutch guy named Schoop.

    Inquiring minds and all--is that "scoopadge" or "shoopadge" or
    "showpadge" or some *tertium quid*?

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to legg on Thu Jul 7 18:27:24 2022
    legg wrote:
    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>>
    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?
    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the
    imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.


    I think the rule of thumb takes into account a return
    path for a straight wire separated by a PCB thickness.

    Nah, the 20 nH per inch number is for wire flapping in the breeze, per
    the ARRL Handbook et al. It does depend slightly on the gauge.


    The test jig illustrated has terminals mounted on
    0.75 inch centers.

    If that is being 'nulled', then you'd get a different
    measurement, not the full loop.

    The rolled film cap construction has a larger width
    than a straight wire. This gives the path a reduced
    L/W ration, reducing both R and L.

    Yup. Also, while the field outside doesn't depend on the radial
    distribution of current, the field inside does, and the spiral
    construction forces it to be pretty well uniform.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Phil Hobbs on Thu Jul 7 18:33:27 2022
    Phil Hobbs wrote:
    legg wrote:
    On Thu, 07 Jul 2022 10:07:49 -0700, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:

    <snip>

    The frequency null computes to 8 nH against the 6.8 uF capacitance.
    Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm. But IR is still off the scale on my Fluke
    DVM and it's still a capacitor around its original value.

    https://www.dropbox.com/s/n1gp3h7h1v4bzw6/CDE_Guts.jpg?raw=1

    It appears to be a metalized film spiral that has big metal (flame
    sprayed?) electrodes on both ends.

    . . . . . called 'schoopage'.


    We'll use lots of these so it's good to understand them.

    RL

    Fun--named after a Dutch guy named Schoop.

    Inquiring minds and all--is that "scoopadge" or "shoopadge" or
    "showpadge" or some *tertium quid*?

    Never mind, he was Swiss, so I expect that means it's roughly
    "scope-age", with a bit of "soup" in the 'o' sound.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Dimiter_Popoff@21:1/5 to John Larkin on Fri Jul 8 01:41:08 2022
    On 7/7/2022 20:07, John Larkin wrote:
    On Thu, 07 Jul 2022 07:51:24 -0700, jlarkin@highlandsniptechnology.com
    wrote:

    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>>>
    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?

    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating
    from ripple current at 250 KHz. I'm better equipped to measure these
    things.

    I like to measure (and explode) parts. I wonder what will happen if I
    put kilovolts into this one. Any guesses?


    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the
    imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.

    Cheers

    Phil Hobbs

    The conductive path, end to end, is probably many concentric cylinders
    of foil, which I guess could have very low inductance. In my
    measurement, the leads themselves seem to dominate L.

    The frequency null computes to 8 nH against the 6.8 uF capacitance.
    Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm. But IR is still off the scale on my Fluke
    DVM and it's still a capacitor around its original value.

    https://www.dropbox.com/s/n1gp3h7h1v4bzw6/CDE_Guts.jpg?raw=1

    It appears to be a metalized film spiral that has big metal (flame
    sprayed?) electrodes on both ends.

    We'll use lots of these so it's good to understand them.



    I am puzzled where the huge inductance, so nicely visible on your
    scope shots, comes from as the layers are all shorted on each
    side.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Allison@21:1/5 to John Larkin on Thu Jul 7 17:28:56 2022
    John Larkin wrote:
    ==================

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?

    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating
    from ripple current at 250 KHz. I'm better equipped to measure these >things.

    ** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.

    I like to measure (and explode) parts. I wonder what will happen if I
    put kilovolts into this one. Any guesses?

    ** I have actually done that.

    250VAC* at 10 to 20kHz will smoke nearly any such cap in seconds.

    * 50watt audio amp driving cap and 1 to 5mH air core choke in series at resonance - big fun.


    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm.

    ** Polyester caps are quite fragile, even at 50/60Hz they will fail over time below rated AC voltage.

    The issue is internal trapped air pockets and corona discharge across same.
    Class X1 and X2 types are "double wound " so act as 2 in series to stop this.

    Seems winding in vaccuo is just too damn hard.


    ..... Phil

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to All on Thu Jul 7 18:25:09 2022
    On Fri, 8 Jul 2022 01:41:08 +0300, Dimiter_Popoff <dp@tgi-sci.com>
    wrote:

    On 7/7/2022 20:07, John Larkin wrote:
    On Thu, 07 Jul 2022 07:51:24 -0700, jlarkin@highlandsniptechnology.com
    wrote:

    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?

    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating >>>from ripple current at 250 KHz. I'm better equipped to measure these
    things.

    I like to measure (and explode) parts. I wonder what will happen if I
    put kilovolts into this one. Any guesses?


    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the
    imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.

    Cheers

    Phil Hobbs

    The conductive path, end to end, is probably many concentric cylinders
    of foil, which I guess could have very low inductance. In my
    measurement, the leads themselves seem to dominate L.

    The frequency null computes to 8 nH against the 6.8 uF capacitance.
    Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm. But IR is still off the scale on my Fluke
    DVM and it's still a capacitor around its original value.

    https://www.dropbox.com/s/n1gp3h7h1v4bzw6/CDE_Guts.jpg?raw=1

    It appears to be a metalized film spiral that has big metal (flame
    sprayed?) electrodes on both ends.

    We'll use lots of these so it's good to understand them.



    I am puzzled where the huge inductance, so nicely visible on your
    scope shots, comes from as the layers are all shorted on each
    side.

    8 nH isn't huge. Extending the wire leads up an extra half inch
    triples the inductive spikes.

    The leads aren't even zero length on those Pomona adapters. Inductance
    would be even lower if the cap were soldered onto a pcb's power pours.

    I should try that, just for fun. The caps are plenty good enough for
    our power supply uses.

    At our voltages, we need films because ceramic caps will lose all
    their C.


    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Allison@21:1/5 to John Larkin on Thu Jul 7 19:04:23 2022
    John Larkin wrote:
    ==============


    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating
    from ripple current at 250 KHz. I'm better equipped to measure these
    things.

    ** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.

    We did some testing today. One of these caps runs cold at 48 VDC and
    half an amp RMS ripple curent at 250 KHz.

    ** So the ripple voltage is TINY !!
    It's the di-electric loss in the film that heats.


    ...... Phil

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to pallison49@gmail.com on Thu Jul 7 18:28:26 2022
    On Thu, 7 Jul 2022 17:28:56 -0700 (PDT), Phil Allison
    <pallison49@gmail.com> wrote:

    John Larkin wrote:
    ==================

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?

    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating
    from ripple current at 250 KHz. I'm better equipped to measure these
    things.

    ** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.

    We did some testing today. One of these caps runs cold at 48 VDC and
    half an amp RMS ripple curent at 250 KHz. And we'll run four in
    parallel.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Thu Jul 7 19:46:12 2022
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    legg wrote:
    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>>>
    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?
    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the
    imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.


    I think the rule of thumb takes into account a return
    path for a straight wire separated by a PCB thickness.

    Nah, the 20 nH per inch number is for wire flapping in the breeze, per
    the ARRL Handbook et al. It does depend slightly on the gauge.


    The test jig illustrated has terminals mounted on
    0.75 inch centers.

    If that is being 'nulled', then you'd get a different
    measurement, not the full loop.

    The rolled film cap construction has a larger width
    than a straight wire. This gives the path a reduced
    L/W ration, reducing both R and L.

    Yup. Also, while the field outside doesn't depend on the radial
    distribution of current, the field inside does, and the spiral
    construction forces it to be pretty well uniform.

    Cheers

    Phil Hobbs

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Allison@21:1/5 to John Larkin on Thu Jul 7 19:43:52 2022
    John Larkin wrote:
    ==============


    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating >> >> >from ripple current at 250 KHz. I'm better equipped to measure these >> >> >things.

    ** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.

    We did some testing today. One of these caps runs cold at 48 VDC and
    half an amp RMS ripple curent at 250 KHz.

    ** So the ripple voltage is TINY !!
    That's what the caps are for!


    ** But kept secret about so you could troll everyone.
    Just like you have been doing for 25 years here.

    Peeeeeeuukkkeeeeee !!!!!!!!!!!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pallison49@gmail.com on Thu Jul 7 19:38:24 2022
    On Thu, 7 Jul 2022 19:04:23 -0700 (PDT), Phil Allison
    <pallison49@gmail.com> wrote:

    John Larkin wrote:
    ==============


    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating
    from ripple current at 250 KHz. I'm better equipped to measure these
    things.

    ** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.

    We did some testing today. One of these caps runs cold at 48 VDC and
    half an amp RMS ripple curent at 250 KHz.

    ** So the ripple voltage is TINY !!

    That's what the caps are for!



    It's the di-electric loss in the film that heats.


    ...... Phil

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Anthony William Sloman@21:1/5 to jla...@highlandsniptechnology.com on Thu Jul 7 20:19:30 2022
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    <snip>

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures? The industry as a whole presumably finds them reliable enough.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From legg@21:1/5 to bill.sloman@ieee.org on Thu Jul 7 23:44:15 2022
    On Thu, 7 Jul 2022 20:19:30 -0700 (PDT), Anthony William Sloman <bill.sloman@ieee.org> wrote:

    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    <snip>

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures? The industry as a whole presumably finds them reliable enough.

    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on
    the sheared edges.

    They need to be sealed to survive, so conformal coatings or
    encapsulation of the final assy is required.

    RL

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pallison49@gmail.com on Thu Jul 7 20:53:06 2022
    On Thu, 7 Jul 2022 19:43:52 -0700 (PDT), Phil Allison
    <pallison49@gmail.com> wrote:

    John Larkin wrote:
    ==============


    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating >> >> >> >from ripple current at 250 KHz. I'm better equipped to measure these >> >> >> >things.

    ** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.

    We did some testing today. One of these caps runs cold at 48 VDC and
    half an amp RMS ripple curent at 250 KHz.

    ** So the ripple voltage is TINY !!
    That's what the caps are for!


    ** But kept secret about so you could troll everyone.
    Just like you have been doing for 25 years here.

    Peeeeeeuukkkeeeeee !!!!!!!!!!!




    The post that started this thread said what I'm doing, namely building
    an LC filter in a switching regulator.

    No secret there.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Allison@21:1/5 to All on Thu Jul 7 23:19:07 2022
    JL is a trolling shithead

    ===============================


    ** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.

    We did some testing today. One of these caps runs cold at 48 VDC and
    half an amp RMS ripple curent at 250 KHz.

    ** So the ripple voltage is TINY !!

    That's what the caps are for!

    ** But kept secret about so you could troll everyone.
    Just like you have been doing for 25 years here.

    Peeeeeeuukkkeeeeee !!!!!!!!!!!


    The post that started this thread said what I'm doing,

    ** Like hell it did.

    " We want some biggish film caps to use in some LC filters for a couple
    of switching power things "

    ** Reveals NOTHING.
    Exactly like ALL your bullshit posts.

    Wot a fake.


    ...... Phil

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Fri Jul 8 09:40:56 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    legg wrote:
    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?
    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the
    imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.


    I think the rule of thumb takes into account a return
    path for a straight wire separated by a PCB thickness.

    Nah, the 20 nH per inch number is for wire flapping in the breeze, per
    the ARRL Handbook et al. It does depend slightly on the gauge.


    The test jig illustrated has terminals mounted on
    0.75 inch centers.

    If that is being 'nulled', then you'd get a different
    measurement, not the full loop.

    The rolled film cap construction has a larger width
    than a straight wire. This gives the path a reduced
    L/W ration, reducing both R and L.

    Yup. Also, while the field outside doesn't depend on the radial
    distribution of current, the field inside does, and the spiral
    construction forces it to be pretty well uniform.

    Cheers

    Phil Hobbs

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.


    I've never used a SMT film cap on account of all the horror stories. I
    recall someone here posting a Digikey product page for one, with a photo
    that clearly showed delamination before it even got onto a board!

    [Just checked--it was you, in a 2015 thread titled "delaminated caps",
    but the Dropbox links are (inevitably) dead.]

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Fri Jul 8 07:31:30 2022
    On Fri, 8 Jul 2022 09:40:56 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    legg wrote:
    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?
    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the >>>>> imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.


    I think the rule of thumb takes into account a return
    path for a straight wire separated by a PCB thickness.

    Nah, the 20 nH per inch number is for wire flapping in the breeze, per
    the ARRL Handbook et al. It does depend slightly on the gauge.


    The test jig illustrated has terminals mounted on
    0.75 inch centers.

    If that is being 'nulled', then you'd get a different
    measurement, not the full loop.

    The rolled film cap construction has a larger width
    than a straight wire. This gives the path a reduced
    L/W ration, reducing both R and L.

    Yup. Also, while the field outside doesn't depend on the radial
    distribution of current, the field inside does, and the spiral
    construction forces it to be pretty well uniform.

    Cheers

    Phil Hobbs

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.


    I've never used a SMT film cap on account of all the horror stories. I
    recall someone here posting a Digikey product page for one, with a photo
    that clearly showed delamination before it even got onto a board!

    [Just checked--it was you, in a 2015 thread titled "delaminated caps",
    but the Dropbox links are (inevitably) dead.]

    Cheers

    Phil Hobbs

    I don't know why people still sell these horrors. I've never seen one
    on a piece of production gear.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pallison49@gmail.com on Fri Jul 8 07:29:23 2022
    On Thu, 7 Jul 2022 23:19:07 -0700 (PDT), Phil Allison
    <pallison49@gmail.com> wrote:

    JL is a trolling shithead

    ===============================


    ** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.

    We did some testing today. One of these caps runs cold at 48 VDC and >> >> >> half an amp RMS ripple curent at 250 KHz.

    ** So the ripple voltage is TINY !!

    That's what the caps are for!

    ** But kept secret about so you could troll everyone.
    Just like you have been doing for 25 years here.

    Peeeeeeuukkkeeeeee !!!!!!!!!!!


    The post that started this thread said what I'm doing,

    ** Like hell it did.

    " We want some biggish film caps to use in some LC filters for a couple
    of switching power things "

    ** Reveals NOTHING.
    Exactly like ALL your bullshit posts.

    Wot a fake.


    ...... Phil

    The problem was pretty clear. If the issue interested you, and you
    didn't understand what I'm doing, you could have asked.

    The filter is actually interesting. We have a 60-volt 250 KHz 2-fet
    half-bridge and it needs to be lowpass filtered to make a clean 0 to
    36 volt programmable DC power supply. We'll digitize the final output
    voltage and current and close the loops in an FPGA, which then makes
    the PWM into the fets. So the filter needs to really kill the 250 KHz
    ripple (without frying itself) but have low phase shift and low Q so
    it doesn't wreck the control loop. And it has to be made out of parts
    that we have or can actually buy now.

    Turns out that, among other things, the Rds-on of the fets is an
    important part of the filter response.

    We sim'd this with the LTC4444 gate drivers but prefer to use the TI
    UCC27712. We just tested that and it's excellent. Ignoring the data
    sheet, we just connect directly to the fet gates.

    Here's my little half-bridge test board, before massive hacks:

    https://www.dropbox.com/s/2x8z6yn29ab57xf/Z524_Wing_1.jpg?raw=1

    It's regulating 200 watts and barely getting warm.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to jlarkin@highland_atwork_technology. on Fri Jul 8 13:30:21 2022
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin <jlarkin@highland_atwork_technology.com> wrote:


    We want some biggish film caps to use in some LC filters for a couple
    of switching power things, so we got some to test.

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
    into the test rig with longer leads the ESL spikes go way up,
    consistent with the loop area, so the low ESL seems real. It will be
    even lower soldered on a PCB, into some hunky copper planes.

    Of course ESL is not a lumped property of a wound film cap, but this
    is close.

    We were considering some big ceramic caps, but they lose 80% of their
    c at our 48 volts DC.

    Here's a test of the c-v of a ceramic cap. We'll run at 60 volts as a
    supply bypass, so we'll get about 1.2 uF, which will be OK if we put a
    few in parallel with one big electro. That's smaller and less ESL than
    a giant film cap.

    https://www.dropbox.com/sh/7zlc8v29tgyoxrx/AABIyneKVEV-xX330TZTi4qTa?dl=0

    We still need the big films in the supply output filter.


    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ehsjr@21:1/5 to Anthony William Sloman on Fri Jul 8 18:23:14 2022
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    <snip>

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin
    predujice showing through. It's time someone pointed it out
    to you.

    The industry as a whole presumably finds them reliable enough.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to John Larkin on Fri Jul 8 18:23:48 2022
    John Larkin wrote:
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin <jlarkin@highland_atwork_technology.com> wrote:


    We want some biggish film caps to use in some LC filters for a couple
    of switching power things, so we got some to test.

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
    into the test rig with longer leads the ESL spikes go way up,
    consistent with the loop area, so the low ESL seems real. It will be
    even lower soldered on a PCB, into some hunky copper planes.

    Of course ESL is not a lumped property of a wound film cap, but this
    is close.

    We were considering some big ceramic caps, but they lose 80% of their
    c at our 48 volts DC.

    Here's a test of the c-v of a ceramic cap. We'll run at 60 volts as a
    supply bypass, so we'll get about 1.2 uF, which will be OK if we put a
    few in parallel with one big electro. That's smaller and less ESL than
    a giant film cap.

    https://www.dropbox.com/sh/7zlc8v29tgyoxrx/AABIyneKVEV-xX330TZTi4qTa?dl=0

    We still need the big films in the supply output filter.

    Ceramic caps' C(V) curves are all over the map. The
    drudgery required to find a part that 'achieves' 70% of its rated
    capacitance at *gasp* 30% of its rated voltage has got old, old, old,
    old, and old. (Did I mention old?)

    At this point, when we find a reasonably acceptable one, we hold our
    noses and do a lifetime buy.

    On the plus side, the good manufacturers have websites where you can get reasonably accurate C(V) curves, but the amount of assing around is assssstrononmical.

    Cheerssss

    Phil Hobbsssss

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Anthony William Sloman@21:1/5 to ehsjr on Fri Jul 8 17:01:03 2022
    On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    <snip>

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin prejudice showing through. It's time someone pointed it out to you.

    It was a perfectly sensible question. And it has got a perfectly sensible answer

    The industry as a whole presumably finds them reliable enough.

    As legg pointed out

    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on the sheared edges.

    They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.

    I ended up getting educated because I posted a sensible question. If you want to see a posting sensible questions that gets a sensible answer as an "exhibition of anti-Larkin prejudice" you've got your own kind of problem, and it might be that time
    someone pointed it out to you.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to ehsjr on Fri Jul 8 18:19:10 2022
    On Fri, 8 Jul 2022 18:23:14 -0400, ehsjr <ehsjr@verizon.net> wrote:

    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    <snip>

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin
    predujice showing through. It's time someone pointed it out
    to you.

    The industry as a whole presumably finds them reliable enough.


    He reflexively declares me to be wrong about everything, because his
    emotions totally dominate his ability to reason. Or to use google.

    Ignore him.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Anthony William Sloman@21:1/5 to John Larkin on Fri Jul 8 21:51:59 2022
    On Saturday, July 9, 2022 at 11:19:21 AM UTC+10, John Larkin wrote:
    On Fri, 8 Jul 2022 18:23:14 -0400, ehsjr <eh...@verizon.net> wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    <snip>

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    The industry as a whole presumably finds them reliable enough.

    Nothing. This is just another example of your anti-Larkin
    prejudice showing through. It's time someone pointed it out
    to you.

    He reflexively declares me to be wrong about everything, because his emotions totally dominate his ability to reason. Or to use google.

    Legg pointed out that you should have used a conformable coating on your stacked film capacitors if you were going to put them through a water wash.

    The reasonable point I was making was that you must have got something wrong if you found them to be unreliable. I don't make "reflexive declarations" and I certainly don't claim that you are wrong about everything - though your ideas about anthropogenic
    global warming are remarkably consistently wrong.

    Ignore him.

    Blanket advice, of the kind you were objecting to. If you bothered to read what I actually post, you might produce less reflexive responses, but since what you seem to be looking for is uncritical flattery you are probably right to skip my comments.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From whit3rd@21:1/5 to bill....@ieee.org on Fri Jul 8 22:25:22 2022
    On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote:
    On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin prejudice showing through. It's time someone pointed it out to you.

    It was a perfectly sensible question. And it has got a perfectly sensible answer
    The industry as a whole presumably finds them reliable enough.
    As legg pointed out
    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on the sheared edges.
    They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.

    That seems odd; you don't want to conformal coat before soldering, and you don't want to
    solder, then conformal coat before washing, do you?

    I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
    rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
    otherwise, the conformal coating that matters has to be selectively applied before putting the parts into a reel. One hopes
    the capacitor manufacture process has been designed with this issue in mind.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to All on Sat Jul 9 06:55:21 2022
    On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whit3rd@gmail.com>
    wrote:

    On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote:
    On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    Surface-mount film caps would have lower inductance, but I've always
    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin prejudice showing through. It's time someone pointed it out to you.

    It was a perfectly sensible question. And it has got a perfectly sensible answer
    The industry as a whole presumably finds them reliable enough.
    As legg pointed out
    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on the sheared edges.
    They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.

    That seems odd; you don't want to conformal coat before soldering, and you don't want to
    solder, then conformal coat before washing, do you?

    I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
    rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
    otherwise, the conformal coating that matters has to be selectively applied >before putting the parts into a reel.

    Sounds labor intensive.

    One hopes
    the capacitor manufacture process has been designed with this issue in mind.

    Just use radial leaded film caps.

    When I wanted to see the innards of my brown 6.8u film cap. I put it
    on an anvil and hit it with a hammer. Nothing happened. The way to get
    inside was to put it in a big vise, lengthwise, and squeeze it until
    the shell shattered.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Sat Jul 9 07:46:48 2022
    On Fri, 8 Jul 2022 18:23:48 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    John Larkin wrote:
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:


    We want some biggish film caps to use in some LC filters for a couple
    of switching power things, so we got some to test.

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>
    The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
    into the test rig with longer leads the ESL spikes go way up,
    consistent with the loop area, so the low ESL seems real. It will be
    even lower soldered on a PCB, into some hunky copper planes.

    Of course ESL is not a lumped property of a wound film cap, but this
    is close.

    We were considering some big ceramic caps, but they lose 80% of their
    c at our 48 volts DC.

    Here's a test of the c-v of a ceramic cap. We'll run at 60 volts as a
    supply bypass, so we'll get about 1.2 uF, which will be OK if we put a
    few in parallel with one big electro. That's smaller and less ESL than
    a giant film cap.

    https://www.dropbox.com/sh/7zlc8v29tgyoxrx/AABIyneKVEV-xX330TZTi4qTa?dl=0

    We still need the big films in the supply output filter.

    Ceramic caps' C(V) curves are all over the map. The
    drudgery required to find a part that 'achieves' 70% of its rated
    capacitance at *gasp* 30% of its rated voltage has got old, old, old,
    old, and old. (Did I mention old?)

    At this point, when we find a reasonably acceptable one, we hold our
    noses and do a lifetime buy.

    On the plus side, the good manufacturers have websites where you can get >reasonably accurate C(V) curves, but the amount of assing around is >assssstrononmical.

    Cheerssss

    Phil Hobbsssss

    There seems to be an unofficial concensus that hi-K ceramic caps are
    are rated for the voltage that makes 10% of their rated capacitance.
    They can generally stand several times that voltage.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bitrex@21:1/5 to John Larkin on Sat Jul 9 12:38:00 2022
    On 7/7/2022 1:07 PM, John Larkin wrote:
    On Thu, 07 Jul 2022 07:51:24 -0700, jlarkin@highlandsniptechnology.com
    wrote:

    On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Allison wrote:
    John Larkin wrote:
    ===============

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>>>
    The 8 nH ESL number is shocking, hard to believe,

    ** Did you read the maker's spec?

    No, I tested a few sample caps for another engineer, to check his
    power supply Spice model and see if we'll have a problem with heating
    from ripple current at 250 KHz. I'm better equipped to measure these
    things.

    I like to measure (and explode) parts. I wonder what will happen if I
    put kilovolts into this one. Any guesses?


    Says <1nH per mm of body and lead length.

    It's a bog standard, Ilinois Capacitor: MMR series, metallised polyester.

    https://www.farnell.com/datasheets/2900812.pdf


    The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the
    imperially challenged). However, that cap is 26 mm long, not even
    counting the banana connectors, which ought to be above 20 nH.

    Cheers

    Phil Hobbs

    The conductive path, end to end, is probably many concentric cylinders
    of foil, which I guess could have very low inductance. In my
    measurement, the leads themselves seem to dominate L.

    The frequency null computes to 8 nH against the 6.8 uF capacitance.
    Things may not be that simple, but the tiny net impedance seems real.

    I have a cool LCF program if anyone is interested.

    I connected it to my trusty ole (it has one tube!) Kepco HV supply. I
    was expecting a kilovolt at least, but at 250 volts it made popping
    frying noises and got warm. But IR is still off the scale on my Fluke
    DVM and it's still a capacitor around its original value.

    https://www.dropbox.com/s/n1gp3h7h1v4bzw6/CDE_Guts.jpg?raw=1

    It appears to be a metalized film spiral that has big metal (flame
    sprayed?) electrodes on both ends.

    We'll use lots of these so it's good to understand them.



    Which tube is it? Using up those surplus TV shunt regulators?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Sat Jul 9 12:30:23 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whit3rd@gmail.com>
    wrote:

    On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote:
    On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    Surface-mount film caps would have lower inductance, but I've always >>>>>> found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin prejudice showing through. It's time someone pointed it out to you.

    It was a perfectly sensible question. And it has got a perfectly sensible answer
    The industry as a whole presumably finds them reliable enough.
    As legg pointed out
    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on the sheared edges.
    They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.

    That seems odd; you don't want to conformal coat before soldering, and you don't want to
    solder, then conformal coat before washing, do you?

    I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
    rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
    otherwise, the conformal coating that matters has to be selectively applied >> before putting the parts into a reel.

    Sounds labor intensive.

    One hopes
    the capacitor manufacture process has been designed with this issue in mind.

    Just use radial leaded film caps.

    When I wanted to see the innards of my brown 6.8u film cap. I put it
    on an anvil and hit it with a hammer. Nothing happened. The way to get
    inside was to put it in a big vise, lengthwise, and squeeze it until
    the shell shattered.


    Yeah, through-hole film caps rock. They're really the only technology
    for applications needing good linearity at higher CV values than you can
    get in C0G. One typical use for us is filtering the bias supplies for avalanche photodiodes and SiPMs, but they're also good for slow analog
    ramps.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bitrex@21:1/5 to John Larkin on Sat Jul 9 12:46:48 2022
    On 7/8/2022 4:30 PM, John Larkin wrote:
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin <jlarkin@highland_atwork_technology.com> wrote:


    We want some biggish film caps to use in some LC filters for a couple
    of switching power things, so we got some to test.

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0

    The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
    into the test rig with longer leads the ESL spikes go way up,
    consistent with the loop area, so the low ESL seems real. It will be
    even lower soldered on a PCB, into some hunky copper planes.

    Of course ESL is not a lumped property of a wound film cap, but this
    is close.

    We were considering some big ceramic caps, but they lose 80% of their
    c at our 48 volts DC.

    Here's a test of the c-v of a ceramic cap. We'll run at 60 volts as a
    supply bypass, so we'll get about 1.2 uF, which will be OK if we put a
    few in parallel with one big electro. That's smaller and less ESL than
    a giant film cap.

    https://www.dropbox.com/sh/7zlc8v29tgyoxrx/AABIyneKVEV-xX330TZTi4qTa?dl=0

    We still need the big films in the supply output filter.



    I could've sworn I have some Xicon polystyrenes at 0.1uF in a box but
    all I find currently available are 0.01 uF:

    <https://www.mouser.com/c/passive-components/capacitors/film-capacitors/?dielectric=Polystyrene%20%28PS%29>

    Have to remember to check what those big fatties are when I get home.
    Maybe they made them bigger at one time.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Sat Jul 9 10:22:56 2022
    On Sat, 9 Jul 2022 12:30:23 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whit3rd@gmail.com>
    wrote:

    On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote:
    On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    Surface-mount film caps would have lower inductance, but I've always >>>>>>> found them to be unreliable. They delaminate and wash water gets >>>>>>> between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin prejudice showing through. It's time someone pointed it out to you.

    It was a perfectly sensible question. And it has got a perfectly sensible answer
    The industry as a whole presumably finds them reliable enough.
    As legg pointed out
    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on the sheared edges.
    They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.

    That seems odd; you don't want to conformal coat before soldering, and you don't want to
    solder, then conformal coat before washing, do you?

    I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
    rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
    otherwise, the conformal coating that matters has to be selectively applied >>> before putting the parts into a reel.

    Sounds labor intensive.

    One hopes
    the capacitor manufacture process has been designed with this issue in mind.

    Just use radial leaded film caps.

    When I wanted to see the innards of my brown 6.8u film cap. I put it
    on an anvil and hit it with a hammer. Nothing happened. The way to get
    inside was to put it in a big vise, lengthwise, and squeeze it until
    the shell shattered.


    Yeah, through-hole film caps rock. They're really the only technology
    for applications needing good linearity at higher CV values than you can
    get in C0G. One typical use for us is filtering the bias supplies for >avalanche photodiodes and SiPMs, but they're also good for slow analog
    ramps.

    Cheers

    Phil Hobbs

    What's best these days for low D.A?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to bitrex on Sat Jul 9 10:26:00 2022
    On Sat, 9 Jul 2022 12:46:48 -0400, bitrex <user@example.net> wrote:

    On 7/8/2022 4:30 PM, John Larkin wrote:
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:


    We want some biggish film caps to use in some LC filters for a couple
    of switching power things, so we got some to test.

    The best one is this ugly brown radial-lead CDE thing.

    https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0 >>>
    The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
    into the test rig with longer leads the ESL spikes go way up,
    consistent with the loop area, so the low ESL seems real. It will be
    even lower soldered on a PCB, into some hunky copper planes.

    Of course ESL is not a lumped property of a wound film cap, but this
    is close.

    We were considering some big ceramic caps, but they lose 80% of their
    c at our 48 volts DC.

    Here's a test of the c-v of a ceramic cap. We'll run at 60 volts as a
    supply bypass, so we'll get about 1.2 uF, which will be OK if we put a
    few in parallel with one big electro. That's smaller and less ESL than
    a giant film cap.

    https://www.dropbox.com/sh/7zlc8v29tgyoxrx/AABIyneKVEV-xX330TZTi4qTa?dl=0

    We still need the big films in the supply output filter.



    I could've sworn I have some Xicon polystyrenes at 0.1uF in a box but
    all I find currently available are 0.01 uF:

    <https://www.mouser.com/c/passive-components/capacitors/film-capacitors/?dielectric=Polystyrene%20%28PS%29>

    Have to remember to check what those big fatties are when I get home.
    Maybe they made them bigger at one time.

    Those are great but chemically/physically/thermally fragile.
    Accidentally touch one with a soldering iron and they die.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Sat Jul 9 13:50:48 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 12:30:23 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whit3rd@gmail.com>
    wrote:

    On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote: >>>>> On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    Surface-mount film caps would have lower inductance, but I've always >>>>>>>> found them to be unreliable. They delaminate and wash water gets >>>>>>>> between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin prejudice showing through. It's time someone pointed it out to you.

    It was a perfectly sensible question. And it has got a perfectly sensible answer
    The industry as a whole presumably finds them reliable enough.
    As legg pointed out
    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on the sheared edges.
    They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.

    That seems odd; you don't want to conformal coat before soldering, and you don't want to
    solder, then conformal coat before washing, do you?

    I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
    rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
    otherwise, the conformal coating that matters has to be selectively applied
    before putting the parts into a reel.

    Sounds labor intensive.

    One hopes
    the capacitor manufacture process has been designed with this issue in mind.

    Just use radial leaded film caps.

    When I wanted to see the innards of my brown 6.8u film cap. I put it
    on an anvil and hit it with a hammer. Nothing happened. The way to get
    inside was to put it in a big vise, lengthwise, and squeeze it until
    the shell shattered.


    Yeah, through-hole film caps rock. They're really the only technology
    for applications needing good linearity at higher CV values than you can
    get in C0G. One typical use for us is filtering the bias supplies for
    avalanche photodiodes and SiPMs, but they're also good for slow analog
    ramps.

    Cheers

    Phil Hobbs

    What's best these days for low D.A?


    Seems like all the work on film caps centers on high temperatures, for
    obvious reasons--the old faithful mylar (polyester), polypropylene, and (especially) polystyrene dielectrics won't stand SMT reflow. The best
    of the newer materials is polyphenylene sulfide (PPS). The newer,
    cheaper alternative is polyethylene naphthalate (PEN), but it has, like,
    2 orders of magnitude worse soakage than PPS.

    Polystyrene melts at around 100C, but is otherwise about the best
    dielectric out there--super low soakage, super low leakage, excellent linearity. Unfortunately it isn't out there much anymore.

    The only outfit I know of that sells them these days is Xicon, and I've
    never used theirs. I should try them out--BITD polystyrene caps mostly
    came in

    Teflon is also super good, but is a bit of a cottage industry at this point--there are tales told about the inability of suppliers (of the
    teflon film stock) to maintain quality.

    Polyester is pretty good except for its weird cubic tempco curve.

    So for the most part I use polypropylene.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Phil Hobbs on Sat Jul 9 15:14:21 2022
    Phil Hobbs wrote:
    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 12:30:23 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whit3rd@gmail.com>
    wrote:

    On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote: >>>>>> On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10,
    jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs
    <pcdhSpamM...@electrooptical.net> wrote:

    Surface-mount film caps would have lower inductance, but I've >>>>>>>>> always
    found them to be unreliable. They delaminate and wash water gets >>>>>>>>> between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin
    prejudice showing through. It's time someone pointed it out to you. >>>>>>
    It was a perfectly sensible question. And it has got a perfectly
    sensible answer
    The industry as a whole presumably finds them reliable enough.
    As legg pointed out
    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on the >>>>>>> sheared edges.
    They need to be sealed to survive, so conformal coatings
    encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were
    inadequate, but rather his failure to apply a conformal coating to >>>>>> what he clearly now knows to be a vulnerable part.

    That seems odd; you don't want to conformal coat before soldering,
    and you don't want to
    solder, then conformal coat before washing, do you?

    I suppose you could install wire-wrap posts, clean the board, but
    conformal coat (the capacitors), then
    rely on wire-wrap attachment of the capacitors to
    insulation-displace the coating...
    otherwise, the conformal coating that matters has to be selectively
    applied
    before putting the parts into a reel.

    Sounds labor intensive.

        One hopes
    the capacitor manufacture process has been designed with this issue
    in mind.

    Just use radial leaded film caps.

    When I wanted to see the innards of my brown 6.8u film cap. I put it
    on an anvil and hit it with a hammer. Nothing happened. The way to get >>>> inside was to put it in a big vise, lengthwise, and squeeze it until
    the shell shattered.


    Yeah, through-hole film caps rock. They're really the only technology
    for applications needing good linearity at higher CV values than you can >>> get in C0G.  One typical use for us is filtering the bias supplies for
    avalanche photodiodes and SiPMs, but they're also good for slow analog
    ramps.

    Cheers

    Phil Hobbs

    What's best these days for low D.A?


    Seems like all the work on film caps centers on high temperatures, for obvious reasons--the old faithful mylar (polyester), polypropylene, and (especially) polystyrene dielectrics won't stand SMT reflow.  The best
    of the newer materials is polyphenylene sulfide (PPS).  The newer,
    cheaper alternative is polyethylene naphthalate (PEN), but it has, like,
    2 orders of magnitude worse soakage than PPS.

    Polystyrene melts at around 100C, but is otherwise about the best
    dielectric out there--super low soakage, super low leakage, excellent linearity.  Unfortunately it isn't out there much anymore.

    The only outfit I know of that sells them these days is Xicon, and I've
    never used theirs.  I should try them out--BITD polystyrene caps mostly
    came in

    1% tolerances at very high prices, but these 5% ones look like they
    might be OK, and they're sure cheaper.


    Teflon is also super good, but is a bit of a cottage industry at this point--there are tales told about the inability of suppliers (of the
    teflon film stock) to maintain quality.

    Polyester is pretty good except for its weird cubic tempco curve.

    So for the most part I use polypropylene.

    Cheers

    Phil Hobbs



    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Sat Jul 9 17:49:22 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 12:46:48 -0400, bitrex <user@example.net> wrote:

    On 7/8/2022 4:30 PM, John Larkin wrote:
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:
    <snip>

    We still need the big films in the supply output filter.



    I could've sworn I have some Xicon polystyrenes at 0.1uF in a box but
    all I find currently available are 0.01 uF:

    <https://www.mouser.com/c/passive-components/capacitors/film-capacitors/?dielectric=Polystyrene%20%28PS%29>

    Have to remember to check what those big fatties are when I get home.
    Maybe they made them bigger at one time.

    Those are great but chemically/physically/thermally fragile.
    Accidentally touch one with a soldering iron and they die.

    "Doctor, Doctor, it hurts when I go like this!"

    "So don't go like that."

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Sat Jul 9 15:38:38 2022
    On Sat, 9 Jul 2022 17:49:22 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 12:46:48 -0400, bitrex <user@example.net> wrote:

    On 7/8/2022 4:30 PM, John Larkin wrote:
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:
    <snip>

    We still need the big films in the supply output filter.



    I could've sworn I have some Xicon polystyrenes at 0.1uF in a box but
    all I find currently available are 0.01 uF:

    <https://www.mouser.com/c/passive-components/capacitors/film-capacitors/?dielectric=Polystyrene%20%28PS%29>

    Have to remember to check what those big fatties are when I get home.
    Maybe they made them bigger at one time.

    Those are great but chemically/physically/thermally fragile.
    Accidentally touch one with a soldering iron and they die.

    "Doctor, Doctor, it hurts when I go like this!"

    "So don't go like that."

    Cheers

    Phil Hobbs

    Doctor, Doctor, it hurts when I breathe!


    Actually, the best non-vacuum caps are SiO2 layers in ICs. That's why
    they are used in SAR ADCs.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bitrex@21:1/5 to Phil Hobbs on Sat Jul 9 18:56:41 2022
    On 7/9/2022 5:49 PM, Phil Hobbs wrote:
    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 12:46:48 -0400, bitrex <user@example.net> wrote:

    On 7/8/2022 4:30 PM, John Larkin wrote:
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:
    <snip>

    We still need the big films in the supply output filter.



    I could've sworn I have some Xicon polystyrenes at 0.1uF in a box but
    all I find currently available are 0.01 uF:

    <https://www.mouser.com/c/passive-components/capacitors/film-capacitors/?dielectric=Polystyrene%20%28PS%29>


    Have to remember to check what those big fatties are when I get home.
    Maybe they made them bigger at one time.

    Those are great but chemically/physically/thermally fragile.
    Accidentally touch one with a soldering iron and they die.

    "Doctor, Doctor, it hurts when I go like this!"

    "So don't go like that."

    Cheers

    Phil Hobbs


    They do tend to give you about 3" worth of lead on each end of the axial polystyrenes. I've never used them above a few 100s of kHz as it's my understanding they're kinda lousy in the MHz range even without the lead inductance. But down lower in e.g. integrator they're basically ideal caps

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bitrex@21:1/5 to jlarkin@highlandsniptechnology.com on Sat Jul 9 19:07:38 2022
    On 7/9/2022 6:38 PM, jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 17:49:22 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 12:46:48 -0400, bitrex <user@example.net> wrote:

    On 7/8/2022 4:30 PM, John Larkin wrote:
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:
    <snip>

    We still need the big films in the supply output filter.



    I could've sworn I have some Xicon polystyrenes at 0.1uF in a box but
    all I find currently available are 0.01 uF:

    <https://www.mouser.com/c/passive-components/capacitors/film-capacitors/?dielectric=Polystyrene%20%28PS%29>

    Have to remember to check what those big fatties are when I get home.
    Maybe they made them bigger at one time.

    Those are great but chemically/physically/thermally fragile.
    Accidentally touch one with a soldering iron and they die.

    "Doctor, Doctor, it hurts when I go like this!"

    "So don't go like that."

    Cheers

    Phil Hobbs

    Doctor, Doctor, it hurts when I breathe!


    Actually, the best non-vacuum caps are SiO2 layers in ICs. That's why
    they are used in SAR ADCs.



    Big fatties!

    <https://www.ebay.com/itm/194980431793>

    A little smaller than a sewing thimble, IIRC. I think the fattest
    non-electro caps I have in my bin are some 1uF 1000 volt metalized polypropylene, those are getting into could-injure-someone-if-you-threw-it-at-them size.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Carl@21:1/5 to Phil Hobbs on Sat Jul 9 20:47:09 2022
    On 7/9/22 15:14, Phil Hobbs wrote:
    Phil Hobbs wrote:
    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 12:30:23 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whit3rd@gmail.com> >>>>> wrote:

    On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote: >>>>>>> On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10,
    jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs
    <pcdhSpamM...@electrooptical.net> wrote:

    Surface-mount film caps would have lower inductance, but I've >>>>>>>>>> always
    found them to be unreliable. They delaminate and wash water gets >>>>>>>>>> between the layers.

    So what's wrong with John Larkin's board-cleaning procedures? >>>>>>>> Nothing. This is just another example of your anti-Larkin
    prejudice showing through. It's time someone pointed it out to you. >>>>>>>
    It was a perfectly sensible question. And it has got a perfectly >>>>>>> sensible answer
    The industry as a whole presumably finds them reliable enough. >>>>>>> As legg pointed out
    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on
    the sheared edges.
    They need to be sealed to survive, so conformal coatings
    encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were
    inadequate, but rather his failure to apply a conformal coating
    to what he clearly now knows to be a vulnerable part.

    That seems odd; you don't want to conformal coat before soldering, >>>>>> and you don't want to
    solder, then conformal coat before washing, do you?

    I suppose you could install wire-wrap posts, clean the board, but
    conformal coat (the capacitors), then
    rely on wire-wrap attachment of the capacitors to
    insulation-displace the coating...
    otherwise, the conformal coating that matters has to be
    selectively applied
    before putting the parts into a reel.

    Sounds labor intensive.

        One hopes
    the capacitor manufacture process has been designed with this
    issue in mind.

    Just use radial leaded film caps.

    When I wanted to see the innards of my brown 6.8u film cap. I put it >>>>> on an anvil and hit it with a hammer. Nothing happened. The way to get >>>>> inside was to put it in a big vise, lengthwise, and squeeze it until >>>>> the shell shattered.


    Yeah, through-hole film caps rock. They're really the only technology
    for applications needing good linearity at higher CV values than you
    can
    get in C0G.  One typical use for us is filtering the bias supplies for >>>> avalanche photodiodes and SiPMs, but they're also good for slow analog >>>> ramps.

    Cheers

    Phil Hobbs

    What's best these days for low D.A?


    Seems like all the work on film caps centers on high temperatures, for
    obvious reasons--the old faithful mylar (polyester), polypropylene,
    and (especially) polystyrene dielectrics won't stand SMT reflow.  The
    best of the newer materials is polyphenylene sulfide (PPS).  The
    newer, cheaper alternative is polyethylene naphthalate (PEN), but it
    has, like, 2 orders of magnitude worse soakage than PPS.

    Polystyrene melts at around 100C, but is otherwise about the best
    dielectric out there--super low soakage, super low leakage, excellent
    linearity.  Unfortunately it isn't out there much anymore.

    The only outfit I know of that sells them these days is Xicon, and
    I've never used theirs.  I should try them out--BITD polystyrene caps
    mostly came in

    1% tolerances at very high prices, but these 5% ones look like they
    might be OK, and they're sure cheaper.


    Teflon is also super good, but is a bit of a cottage industry at this
    point--there are tales told about the inability of suppliers (of the
    teflon film stock) to maintain quality.

    Polyester is pretty good except for its weird cubic tempco curve.

    So for the most part I use polypropylene.

    Cheers

    Phil Hobbs

    How about PEEK? I did some quick googling and found thin film suppliers
    but no capacitors. Should be good mechanically and thermally but I
    don't know about the things that matter for a capacitor like dielectric constant, D. A., thermal coefficients, etc. PI (Kynar) might also be
    good, and Wikipedia actually said someone claimed to offer one but no
    details were available. If anyone wants to try making some I did find
    one place selling a pack of 15 different films for capacitor R&D that
    includes PEEK and PI, for a mere $2000 :-). https://piezopvdf.com/15-type-polymer-capacitor-film-kit/

    --
    Regards,
    Carl

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Sat Jul 9 23:27:15 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 17:49:22 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 12:46:48 -0400, bitrex <user@example.net> wrote:

    On 7/8/2022 4:30 PM, John Larkin wrote:
    On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:
    <snip>

    We still need the big films in the supply output filter.



    I could've sworn I have some Xicon polystyrenes at 0.1uF in a box but
    all I find currently available are 0.01 uF:

    <https://www.mouser.com/c/passive-components/capacitors/film-capacitors/?dielectric=Polystyrene%20%28PS%29>

    Have to remember to check what those big fatties are when I get home.
    Maybe they made them bigger at one time.

    Those are great but chemically/physically/thermally fragile.
    Accidentally touch one with a soldering iron and they die.

    "Doctor, Doctor, it hurts when I go like this!"

    "So don't go like that."

    Cheers

    Phil Hobbs

    Doctor, Doctor, it hurts when I breathe!


    Actually, the best non-vacuum caps are SiO2 layers in ICs. That's why
    they are used in SAR ADCs.

    Well, the lack of available alternatives has something to do with that
    too. ;)

    Cheers

    Phil Hobbs





    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Carl on Sat Jul 9 23:26:05 2022
    Carl wrote:
    On 7/9/22 15:14, Phil Hobbs wrote:
    Phil Hobbs wrote:
    jlarkin@highlandsniptechnology.com wrote:
    On Sat, 9 Jul 2022 12:30:23 -0400, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whit3rd@gmail.com> >>>>>> wrote:

    On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org
    wrote:
    On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10,
    jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs
    <pcdhSpamM...@electrooptical.net> wrote:

    Surface-mount film caps would have lower inductance, but I've >>>>>>>>>>> always
    found them to be unreliable. They delaminate and wash water gets >>>>>>>>>>> between the layers.

    So what's wrong with John Larkin's board-cleaning procedures? >>>>>>>>> Nothing. This is just another example of your anti-Larkin
    prejudice showing through. It's time someone pointed it out to >>>>>>>>> you.

    It was a perfectly sensible question. And it has got a perfectly >>>>>>>> sensible answer
    The industry as a whole presumably finds them reliable enough. >>>>>>>> As legg pointed out
    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on >>>>>>>>> the sheared edges.
    They need to be sealed to survive, so conformal coatings
    encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were >>>>>>>> inadequate, but rather his failure to apply a conformal coating >>>>>>>> to what he clearly now knows to be a vulnerable part.

    That seems odd; you don't want to conformal coat before
    soldering, and you don't want to
    solder, then conformal coat before washing, do you?

    I suppose you could install wire-wrap posts, clean the board, but >>>>>>> conformal coat (the capacitors), then
    rely on wire-wrap attachment of the capacitors to
    insulation-displace the coating...
    otherwise, the conformal coating that matters has to be
    selectively applied
    before putting the parts into a reel.

    Sounds labor intensive.

        One hopes
    the capacitor manufacture process has been designed with this
    issue in mind.

    Just use radial leaded film caps.

    When I wanted to see the innards of my brown 6.8u film cap. I put it >>>>>> on an anvil and hit it with a hammer. Nothing happened. The way to >>>>>> get
    inside was to put it in a big vise, lengthwise, and squeeze it until >>>>>> the shell shattered.


    Yeah, through-hole film caps rock. They're really the only technology >>>>> for applications needing good linearity at higher CV values than
    you can
    get in C0G.  One typical use for us is filtering the bias supplies for >>>>> avalanche photodiodes and SiPMs, but they're also good for slow analog >>>>> ramps.

    Cheers

    Phil Hobbs

    What's best these days for low D.A?


    Seems like all the work on film caps centers on high temperatures,
    for obvious reasons--the old faithful mylar (polyester),
    polypropylene, and (especially) polystyrene dielectrics won't stand
    SMT reflow.  The best of the newer materials is polyphenylene sulfide
    (PPS).  The newer, cheaper alternative is polyethylene naphthalate
    (PEN), but it has, like, 2 orders of magnitude worse soakage than PPS.

    Polystyrene melts at around 100C, but is otherwise about the best
    dielectric out there--super low soakage, super low leakage, excellent
    linearity.  Unfortunately it isn't out there much anymore.

    The only outfit I know of that sells them these days is Xicon, and
    I've never used theirs.  I should try them out--BITD polystyrene caps
    mostly came in

    1% tolerances at very high prices, but these 5% ones look like they
    might be OK, and they're sure cheaper.


    Teflon is also super good, but is a bit of a cottage industry at this
    point--there are tales told about the inability of suppliers (of the
    teflon film stock) to maintain quality.

    Polyester is pretty good except for its weird cubic tempco curve.

    So for the most part I use polypropylene.

    Cheers

    Phil Hobbs

    How about PEEK?  I did some quick googling and found thin film suppliers
    but no capacitors.  Should be good mechanically and thermally but I
    don't know about the things that matter for a capacitor like dielectric constant, D. A., thermal coefficients, etc.  PI (Kynar) might also be
    good, and Wikipedia actually said someone claimed to offer one but no
    details were available.  If anyone wants to try making some I did find
    one place selling a pack of 15 different films for capacitor R&D that includes PEEK and PI, for a mere $2000 :-). https://piezopvdf.com/15-type-polymer-capacitor-film-kit/


    Dunno. There are a lot of things that you'd expect to make good
    dielectrics that don't. Glass caps, for instance, have soakage that has
    to be seen to be believed.

    Cheers

    Phil Hobbs
    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

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  • From Anthony William Sloman@21:1/5 to Phil Hobbs on Sat Jul 9 20:38:33 2022
    On Sunday, July 10, 2022 at 2:30:36 AM UTC+10, Phil Hobbs wrote:
    jla...@highlandsniptechnology.com wrote:
    On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whi...@gmail.com>
    wrote:

    On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote:
    On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    Surface-mount film caps would have lower inductance, but I've always >>>>>> found them to be unreliable. They delaminate and wash water gets >>>>>> between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    Nothing. This is just another example of your anti-Larkin prejudice showing through. It's time someone pointed it out to you.

    It was a perfectly sensible question. And it has got a perfectly sensible answer
    The industry as a whole presumably finds them reliable enough.
    As legg pointed out
    No they don't. They wish they could, but not so far.

    SMT parts are stacked film, without any environmental seal on the sheared edges.
    They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.

    So it wasn't John Larkin's board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.

    That seems odd; you don't want to conformal coat before soldering, and you don't want to
    solder, then conformal coat before washing, do you?

    I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
    rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
    otherwise, the conformal coating that matters has to be selectively applied
    before putting the parts into a reel.

    Sounds labor intensive.

    One hopes
    the capacitor manufacture process has been designed with this issue in mind.

    Just use radial leaded film caps.

    When I wanted to see the innards of my brown 6.8u film cap. I put it
    on an anvil and hit it with a hammer. Nothing happened. The way to get inside was to put it in a big vise, lengthwise, and squeeze it until
    the shell shattered.

    Yeah, through-hole film caps rock. They're really the only technology
    for applications needing good linearity at higher CV values than you can
    get in C0G. One typical use for us is filtering the bias supplies for avalanche photodiodes and SiPMs, but they're also good for slow analog ramps.

    You've got to pick your dielectric film carefully if you want a linear analog ramp. Charge soak can be a problem for polyester films, and polycarbonate films aren't all that much better. Polypropylene films are quite a bit better, and teflon films are
    supposed to be even better, though the films aren't as thin, and teflon is quite a bit more expensive as well.

    --
    Bill Sloman, Sydney

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  • From Jan Panteltje@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Sun Jul 10 06:52:59 2022
    On a sunny day (Sat, 9 Jul 2022 23:26:05 -0400) it happened Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in <tadgsd$1eqe$1@gioia.aioe.org>:

    Dunno. There are a lot of things that you'd expect to make good
    dielectrics that don't. Glass caps, for instance, have soakage that has
    to be seen to be believed.

    Mica?
    Used mica caps in RF years ago.

    This about mica is maybe also interesting:
    https://www.sciencedaily.com/releases/2022/07/220707100502.htm

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  • From Edward's Mother@21:1/5 to Anthony William Sloman on Sun Jul 10 12:14:35 2022
    XPost: free.spam

    No point in discussing anything with Bill "Bozo" Sloman, the Australian
    troll. Bozo is an incessant liar who cannot be reasoned with. Its fiction
    never ends.

    "the user has posted under the same name in other places, so not
    nym-shifting" (Bozo sucks at logic)

    "the Mueller investigation was about Trump only because Trump made it so"
    (Bozo being Bozo)

    "the concepts "male" and "female" are essentially social constructions"
    (Bozo is a textbook cannibal leftist)

    --
    Anthony William Sloman <bill.sloman@ieee.org> wrote:

    X-Received: by 2002:a05:620a:6006:b0:6af:a58:a19 with SMTP id dw6-20020a05620a600600b006af0a580a19mr4741556qkb.534.1657342320214; Fri, 08 Jul 2022 21:52:00 -0700 (PDT)
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    Newsgroups: sci.electronics.design
    Date: Fri, 8 Jul 2022 21:51:59 -0700 (PDT)
    In-Reply-To: <4plhch9e9ba40vepdii7p4qdtde6g67j0e@4ax.com>
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    References: <p4vbchd3p7hda7ht13567244f8l3i3eank@4ax.com> <8a88ec29-dad9-4ff2-81e7-ccfa29caffaen@googlegroups.com> <dabbad17-e6ee-01aa-c40d-f6215b94854c@electrooptical.net> <9ldechh4k15k0u1et5ebqlqtpk5b5pg3go@4ax.com> <ta7mkd$170i$1@gioia.aioe.org> <
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    Message-ID: <595525da-e048-4e94-9f31-810a0d4706b0n@googlegroups.com>
    Subject: Re: film cap test
    From: Anthony William Sloman <bill.sloman@ieee.org>
    Injection-Date: Sat, 09 Jul 2022 04:52:00 +0000
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    Xref: reader01.eternal-september.org sci.electronics.design:673435

    On Saturday, July 9, 2022 at 11:19:21 AM UTC+10, John Larkin wrote:
    On Fri, 8 Jul 2022 18:23:14 -0400, ehsjr <eh...@verizon.net> wrote:
    On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
    On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptech
    nology.com wrote:
    On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electroop
    tical.net> wrote:

    <snip>

    Surface-mount film caps would have lower inductance, but I've always

    found them to be unreliable. They delaminate and wash water gets
    between the layers.

    So what's wrong with John Larkin's board-cleaning procedures?
    The industry as a whole presumably finds them reliable enough.

    Nothing. This is just another example of your anti-Larkin
    prejudice showing through. It's time someone pointed it out
    to you.

    He reflexively declares me to be wrong about everything, because his emot
    ions totally dominate his ability to reason. Or to use google.

    Legg pointed out that you should have used a conformable coating on your stacked film capacitors if you were going to put them through a water wash.

    The reasonable point I was making was that you must have got something wrong if you found them to be unreliable. I don't make "reflexive declarations" and I certainly don't claim that you are wrong about everything - though your ideas about
    anthropogenic global warming are remarkably consistently wrong.

    Ignore him.

    Blanket advice, of the kind you were objecting to. If you bothered to read what I actually post, you might produce less reflexive responses, but since what you seem to be looking for is uncritical flattery you are probably right to skip my comments.

    --
    Bill Sloman, Sydney




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  • From Phil Hobbs@21:1/5 to Jan Panteltje on Sun Jul 10 09:01:01 2022
    Jan Panteltje wrote:
    On a sunny day (Sat, 9 Jul 2022 23:26:05 -0400) it happened Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in <tadgsd$1eqe$1@gioia.aioe.org>:

    Dunno. There are a lot of things that you'd expect to make good
    dielectrics that don't. Glass caps, for instance, have soakage that has
    to be seen to be believed.

    Mica?
    Used mica caps in RF years ago.

    This about mica is maybe also interesting:
    https://www.sciencedaily.com/releases/2022/07/220707100502.htm

    Yup, horrible soakage but great at RF.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

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  • From jlarkin@highlandsniptechnology.com@21:1/5 to always.see@post.header on Sun Jul 10 06:28:00 2022
    XPost: free.spam

    On Sun, 10 Jul 2022 12:14:35 -0000 (UTC), "Edward's Mother" <always.see@post.header> wrote:

    No point in discussing anything with Bill "Bozo" Sloman, the Australian >troll. Bozo is an incessant liar who cannot be reasoned with. Its fiction >never ends.


    He's not a conscious liar. But he is in effect delusional.

    "The easiest person to lie to is yourself."

    Ignore him. Try.

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  • From Anthony William Sloman@21:1/5 to jla...@highlandsniptechnology.com on Sun Jul 10 06:47:17 2022
    On Sunday, July 10, 2022 at 11:28:08 PM UTC+10, jla...@highlandsniptechnology.com wrote:
    On Sun, 10 Jul 2022 12:14:35 -0000 (UTC), "Edward's Mother" <alway...@post.header> wrote:

    No point in discussing anything with Bill "Bozo" Sloman, the Australian >troll. Bozo is an incessant liar who cannot be reasoned with. Its fiction >never ends.

    He's not a conscious liar. But he is in effect delusional.

    I don't share John Larkin's delusions about the quality of his posts here. He thinks they deserve flattery. I'm unkind enough to notice that they don't.

    This doesn't make me "delusional" no matter how much John Larkin would like this to be true.

    "The easiest person to lie to is yourself."

    John Larkin would know. He tells himself that he knows the truth about anthopogenic global warming when he is actually a sucker for half-witted denialist propaganda.

    Ignore him. Try.

    If we could get John Doe to ignore the entire sci.electronics.design user group we'd all be much happier. John Doe doesn't take advice. even John Larkin should have enough sense to have noticed.

    --
    Bill Sloman, Sydney

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  • From Edward Hernandez@21:1/5 to All on Sun Jul 10 15:09:08 2022
    XPost: free.spam

    See also these John Doe troll nym-shift names:
    John Doe <always.look@message.header>
    John <look@post.header>
    Judge Dredd <always.look@post.header>
    "Edward's Mother" <always.see@post.header>

    How stupid is Troll Doe?

    Troll Doe posting one of its vacuous insults at 05:39:20 UTC on 20 Mar
    2022 with a grammatical error:

    http://al.howardknight.net/?ID=164790428800

    Then, at 05:55:56 UTC, 16 minutes and 36 seconds later, Troll Doe
    responds to its own post with a correction, but stupidly forgets that it
    sets a Followup-To: header to the "alt.test.group", resulting in its
    correction article posting only to "alt.test.group":

    http://al.howardknight.net/?ID=164790440700

    Troll Doe, mister "always.look@message.header", is so stupid it does not
    even remember it sets a Followup-To: header in its own vacuous insults.

    Special thanks to corvid <bl@ckb.ird> for pointing out the stupidity of
    Troll Doe:

    http://al.howardknight.net/?ID=165594737000

    The Troll Doe stated the following in message-id
    <sdhn7c$pkp$4@dont-email.me>:

    The troll doesn't even know how to format a USENET post...

    And yet, the clueless Troll Doe has continued to post incorrectly
    formatted USENET articles that are devoid of content (latest example on
    Sun, 10 Jul 2022 12:14:35 -0000 (UTC) in message-id <taefrb$1cc84$2@dont-email.me>).

    NOBODY likes the John Doe troll's contentless spam.

    This posting is a public service announcement for any google groups
    readers who happen by to point out that John Doe does not even follow
    the rules it uses to troll other posters.

    z5pNGmevyrwN

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