• Re: heating a cap

    From Joe Gwinn@21:1/5 to All on Thu Oct 3 20:05:54 2024
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >built-in MOV.

    X-Ray it?

    Joe

    --- SoupGate-Win32 v1.05
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  • From john larkin@21:1/5 to All on Thu Oct 3 16:36:24 2024
    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Robertson@21:1/5 to john larkin on Fri Oct 4 07:09:26 2024
    On 2024-10-03 4:36 p.m., john larkin wrote:
    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a built-in MOV.


    Caps have vents...eventually the electrolyte with evaporate and outgas
    and you are left with a slug of aluminum foil.

    I've seen many thousands of caps fail over the decades, you don't want
    to push them above 85c (even if rated at 105c) unless you like short
    lifetimes. Heck even caps that are never over 50c will dry out
    eventually - 20 to 30 years in many cases. Seals aren't perfect.

    I assume SMD electrolytics are the same.

    Let's not talk about stress testing tantalum caps - "Bang!".

    John ;-#)#

    --
    (Please post followups or tech inquiries to the USENET newsgroup)
    John's Jukes Ltd.
    #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
    (604)872-5757 (Pinballs, Jukes, Video Games)
    www.flippers.com
    "Old pinballers never die, they just flip out."

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Fri Oct 4 07:43:10 2024
    On Fri, 4 Oct 2024 07:09:26 -0700, John Robertson <jrr@flippers.com>
    wrote:

    On 2024-10-03 4:36 p.m., john larkin wrote:
    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.


    Caps have vents...eventually the electrolyte with evaporate and outgas
    and you are left with a slug of aluminum foil.

    I've seen many thousands of caps fail over the decades, you don't want
    to push them above 85c (even if rated at 105c) unless you like short >lifetimes. Heck even caps that are never over 50c will dry out
    eventually - 20 to 30 years in many cases. Seals aren't perfect.

    I assume SMD electrolytics are the same.

    Let's not talk about stress testing tantalum caps - "Bang!".

    John ;-#)#

    The usual MnO2 tantalums actually detonate, and a bit of peak current
    will set them off. The polymer tantalums don't detonate.

    Is there a reason to use polymer tants? I like tantalums for their
    just-right ESR for some voltage regulators, and I think the polymer
    tants are lower.

    If you want low ESR, may as well use a polymer aluminum.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From legg@21:1/5 to All on Fri Oct 4 12:10:38 2024
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >built-in MOV.

    You're not 'heating a cap'.

    You're applying voltage overstress to failure, using a
    current limited source.

    This tells you precisely nothing.

    Were you earing safety glasses?

    Are you sure you want to advertize this increasingly
    erratic behavior?

    RL

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Fri Oct 4 18:00:51 2024
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >built-in MOV.

    That's a hell of sweeping conclusion to come to based on a test of
    just one random electrolytic!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Fri Oct 4 18:03:36 2024
    On Fri, 04 Oct 2024 07:43:10 -0700, john larkin <JL@gct.com> wrote:

    On Fri, 4 Oct 2024 07:09:26 -0700, John Robertson <jrr@flippers.com>
    wrote:

    On 2024-10-03 4:36 p.m., john larkin wrote:
    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.


    Caps have vents...eventually the electrolyte with evaporate and outgas
    and you are left with a slug of aluminum foil.

    I've seen many thousands of caps fail over the decades, you don't want
    to push them above 85c (even if rated at 105c) unless you like short >>lifetimes. Heck even caps that are never over 50c will dry out
    eventually - 20 to 30 years in many cases. Seals aren't perfect.

    I assume SMD electrolytics are the same.

    Let's not talk about stress testing tantalum caps - "Bang!".

    John ;-#)#

    The usual MnO2 tantalums actually detonate, and a bit of peak current
    will set them off. The polymer tantalums don't detonate.

    "Actually detonate" - this is really just a steam explosion we're
    talking about here, though, John? It doesn't involve the breaking
    apart and re-combination of molecular bonds.


    Is there a reason to use polymer tants? I like tantalums for their
    just-right ESR for some voltage regulators, and I think the polymer
    tants are lower.

    If you want low ESR, may as well use a polymer aluminum.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to john larkin on Fri Oct 4 16:24:30 2024
    john larkin <JL@gct.com> wrote:
    On Fri, 4 Oct 2024 07:09:26 -0700, John Robertson <jrr@flippers.com>
    wrote:

    On 2024-10-03 4:36 p.m., john larkin wrote:
    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.


    Caps have vents...eventually the electrolyte with evaporate and outgas
    and you are left with a slug of aluminum foil.

    I've seen many thousands of caps fail over the decades, you don't want
    to push them above 85c (even if rated at 105c) unless you like short
    lifetimes. Heck even caps that are never over 50c will dry out
    eventually - 20 to 30 years in many cases. Seals aren't perfect.

    I assume SMD electrolytics are the same.

    Let's not talk about stress testing tantalum caps - "Bang!".

    John ;-#)#

    The usual MnO2 tantalums actually detonate, and a bit of peak current
    will set them off. The polymer tantalums don't detonate.

    Is there a reason to use polymer tants? I like tantalums for their
    just-right ESR for some voltage regulators, and I think the polymer
    tants are lower.

    If you want low ESR, may as well use a polymer aluminum.



    Some alpos are hybrid, i.e. they have water as well as polymer. I don’t
    think they make hybrid polymer tants.

    Cheers

    Phil Hobbs

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

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to legg on Fri Oct 4 10:31:13 2024
    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer
    to do. Sorry.



    RL

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Fri Oct 4 10:28:48 2024
    On Fri, 04 Oct 2024 18:03:36 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Fri, 04 Oct 2024 07:43:10 -0700, john larkin <JL@gct.com> wrote:

    On Fri, 4 Oct 2024 07:09:26 -0700, John Robertson <jrr@flippers.com>
    wrote:

    On 2024-10-03 4:36 p.m., john larkin wrote:
    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>> built-in MOV.


    Caps have vents...eventually the electrolyte with evaporate and outgas >>>and you are left with a slug of aluminum foil.

    I've seen many thousands of caps fail over the decades, you don't want
    to push them above 85c (even if rated at 105c) unless you like short >>>lifetimes. Heck even caps that are never over 50c will dry out
    eventually - 20 to 30 years in many cases. Seals aren't perfect.

    I assume SMD electrolytics are the same.

    Let's not talk about stress testing tantalum caps - "Bang!".

    John ;-#)#

    The usual MnO2 tantalums actually detonate, and a bit of peak current
    will set them off. The polymer tantalums don't detonate.

    "Actually detonate" - this is really just a steam explosion we're
    talking about here, though, John? It doesn't involve the breaking
    apart and re-combination of molecular bonds.

    As I understand it, a current spike can heat up a tiny bit, and then
    an exothermic chemical reaction takes over. MnO2 is the oxidizer and
    tantalum is the fuel.

    For reliable operation, make sure the available current is limited,
    namely don't use tants on power busses.

    LM317s and output tants seem to work well.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Fri Oct 4 12:44:36 2024
    On Fri, 04 Oct 2024 18:00:51 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>built-in MOV.

    That's a hell of sweeping conclusion to come to based on a test of
    just one random electrolytic!

    It's more data than no experiment would provide.

    Elecs seem to explode from internal steam pressure, which sounds
    fairly predictable.

    But other people here could try it too.

    Film caps fail suddenly at some large multiple of rated voltage.
    Ceramics too, but some start leaking first.

    Is seems like elecs start to leak seriously at about 1.5x rated
    voltage and die from overheating.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to jrwalliker@gmail.com on Fri Oct 4 14:42:34 2024
    On Fri, 4 Oct 2024 19:15:14 +0100, John R Walliker
    <jrwalliker@gmail.com> wrote:

    On 04/10/2024 18:00, Cursitor Doom wrote:
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.

    That's a hell of sweeping conclusion to come to based on a test of
    just one random electrolytic!

    I once tried heating a large electrolytic salvaged from a valve TV.
    With a blowtorch. The side started to bulge, then it split.
    A large flame maybe 1m long emerged, coloured a brilliant green.
    I was wearing safety glasses.
    John

    You could get similar results from a bottle of vodka.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Fri Oct 4 23:50:36 2024
    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>cranked up the voltage. It started drawing a bunch of current at 105 >>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer
    to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an
    out-and-out Commie. Just ignore him.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Fri Oct 4 22:15:50 2024
    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer
    to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to JL@gct.com on Sat Oct 5 06:45:40 2024
    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin <JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer
    to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Sat Oct 5 21:56:04 2024
    On 5/10/2024 5:44 am, john larkin wrote:
    On Fri, 04 Oct 2024 18:00:51 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.

    That's a hell of sweeping conclusion to come to based on a test of
    just one random electrolytic!

    It's more data than no experiment would provide.

    But you'd learn a lot more if you had a better idea of what you were doing.

    Elecs seem to explode from internal steam pressure, which sounds
    fairly predictable.

    But other people here could try it too.

    They could also read up a bit on the chemistry of the particular sort of electrolytic capacitor they were putting under stress.

    Film caps fail suddenly at some large multiple of rated voltage.
    Ceramics too, but some start leaking first.

    There are lots of different ceramic capacitors, from NPO to XR7. Some
    people would be more specific.

    Is seems like electrolytics start to leak seriously at about 1.5x rated voltage and die from overheating.

    A rather sweeping generalisation.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Clive Arthur@21:1/5 to john larkin on Sat Oct 5 13:20:51 2024
    On 04/10/2024 00:36, john larkin wrote:
    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a built-in MOV.


    If you need a high temperature cap, these work and they're not horribly expensive...

    https://www.mouser.co.uk/datasheet/2/40/THJ-3165556.pdf

    --
    Cheers
    Clive

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to clive@nowaytoday.co.uk on Sat Oct 5 13:58:50 2024
    On a sunny day (Sat, 5 Oct 2024 13:20:51 +0100) it happened Clive Arthur <clive@nowaytoday.co.uk> wrote in <vdrav6$ojl5$1@dont-email.me>:

    On 04/10/2024 00:36, john larkin wrote:
    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.


    If you need a high temperature cap, these work and they're not horribly >expensive...

    https://www.mouser.co.uk/datasheet/2/40/THJ-3165556.pdf

    Nice., complete specs, not much need to test yourself..

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to clive@nowaytoday.co.uk on Sat Oct 5 08:09:21 2024
    On Sat, 5 Oct 2024 13:20:51 +0100, Clive Arthur
    <clive@nowaytoday.co.uk> wrote:

    On 04/10/2024 00:36, john larkin wrote:
    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500
    joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.


    If you need a high temperature cap, these work and they're not horribly >expensive...

    https://www.mouser.co.uk/datasheet/2/40/THJ-3165556.pdf

    I reall want to absorb joules when a power supply is back-driven by a
    load, like decelerating a motor for instance. So I want caps with a
    lot of mass, or MOVs that can get very hot before they die.

    The environment won't be very hot, but the cap (or MOV) will.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Sat Oct 5 08:03:14 2024
    On Sat, 05 Oct 2024 06:45:40 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin ><JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    I know people who are terrified of running parts anywhere near abs
    max. I run some parts at 2x abs max voltage or power. Pushing parts is
    the way to get performance, especially speed. Some work fine at 4x.

    Test them, blow up a few, define your own abs max. But only when there
    is a big payoff.

    I'm pushing a lot of HMC659's (15 GHz distributed amplifiers) to about
    2x voltage. It's intimidating to test them to destruction because they
    cost over $300 each.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Sat Oct 5 19:14:04 2024
    On Fri, 04 Oct 2024 22:15:50 -0700, john larkin <JL@gct.com> wrote:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer
    to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    Well, personally speaking, I've derived a great deal of satisfaction
    from doing so over the years.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Sat Oct 5 11:41:23 2024
    On Sat, 05 Oct 2024 19:14:04 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Fri, 04 Oct 2024 22:15:50 -0700, john larkin <JL@gct.com> wrote:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    Well, personally speaking, I've derived a great deal of satisfaction
    from doing so over the years.

    Yes, especially when loud bangs and smoke are involved.

    https://www.dropbox.com/scl/fi/oq1bgzkpsdcsmrg63w1r9/ExFets.jpg?rlkey=jcscvg5vt1qebgyxb0gt5575q&raw=1

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Sat Oct 5 19:18:15 2024
    On Sat, 05 Oct 2024 08:03:14 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 06:45:40 GMT, Jan Panteltje <alien@comet.invalid>
    wrote:

    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin >><JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    I know people who are terrified of running parts anywhere near abs
    max. I run some parts at 2x abs max voltage or power. Pushing parts is
    the way to get performance, especially speed. Some work fine at 4x.

    Test them, blow up a few, define your own abs max. But only when there
    is a big payoff.

    I'm pushing a lot of HMC659's (15 GHz distributed amplifiers) to about
    2x voltage. It's intimidating to test them to destruction because they
    cost over $300 each.

    Surely you are shortening the service life of those components by
    doing this. Just because they survive 24 hours or whatever at 4x
    voltage doesn't tell you everything. They might go 'pop' after a week
    or they might last a year. Either way, it's not good for repeat
    business?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Sat Oct 5 11:38:35 2024
    On Sat, 05 Oct 2024 19:18:15 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sat, 05 Oct 2024 08:03:14 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 06:45:40 GMT, Jan Panteltje <alien@comet.invalid> >>wrote:

    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin >>><JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    I know people who are terrified of running parts anywhere near abs
    max. I run some parts at 2x abs max voltage or power. Pushing parts is
    the way to get performance, especially speed. Some work fine at 4x.

    Test them, blow up a few, define your own abs max. But only when there
    is a big payoff.

    I'm pushing a lot of HMC659's (15 GHz distributed amplifiers) to about
    2x voltage. It's intimidating to test them to destruction because they
    cost over $300 each.

    Surely you are shortening the service life of those components by
    doing this. Just because they survive 24 hours or whatever at 4x
    voltage doesn't tell you everything. They might go 'pop' after a week
    or they might last a year. Either way, it's not good for repeat
    business?

    We have over a century of unit time so far and no problems.

    RF parts have terrible time-domain specs. The datasheets assume that
    the supply voltage is coupled into the drain through an inductor or a
    tank. So at max swing the actual drain voltage goes to 2xVcc. When the
    RF data sheets say "abs max" they mean the supply voltage.

    And they assume (without saying so) that the signal is RF or telecom,
    namely AC coupled and DC balanced. 8b10b or some such.

    So for pulse work, one throws away all that silly S-parameter and dBm
    nonsense. I have a possibly new way to bias the HMC parts for
    electro-optical use; park high, pulse low.

    I wonder what sorts of philosophies various companies have when
    writing data sheet abs max specs.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Sat Oct 5 22:36:47 2024
    On Sat, 05 Oct 2024 11:41:23 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 19:14:04 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Fri, 04 Oct 2024 22:15:50 -0700, john larkin <JL@gct.com> wrote:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    Well, personally speaking, I've derived a great deal of satisfaction
    from doing so over the years.

    Yes, especially when loud bangs and smoke are involved.

    https://www.dropbox.com/scl/fi/oq1bgzkpsdcsmrg63w1r9/ExFets.jpg?rlkey=jcscvg5vt1qebgyxb0gt5575q&raw=1

    Hmm. Electrolytics still give the best bang-per-buck. And the great
    thing is, if they're old and fucked, they still give a great *bang* so
    you don't need to waste costly new parts.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to john larkin on Sat Oct 5 17:25:10 2024
    On Sat, 05 Oct 2024 11:38:35 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 19:18:15 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sat, 05 Oct 2024 08:03:14 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 06:45:40 GMT, Jan Panteltje <alien@comet.invalid> >>>wrote:

    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin >>>><JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>>>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    I know people who are terrified of running parts anywhere near abs
    max. I run some parts at 2x abs max voltage or power. Pushing parts is >>>the way to get performance, especially speed. Some work fine at 4x.

    Test them, blow up a few, define your own abs max. But only when there
    is a big payoff.

    I'm pushing a lot of HMC659's (15 GHz distributed amplifiers) to about
    2x voltage. It's intimidating to test them to destruction because they >>>cost over $300 each.

    Surely you are shortening the service life of those components by
    doing this. Just because they survive 24 hours or whatever at 4x
    voltage doesn't tell you everything. They might go 'pop' after a week
    or they might last a year. Either way, it's not good for repeat
    business?

    We have over a century of unit time so far and no problems.

    RF parts have terrible time-domain specs. The datasheets assume that
    the supply voltage is coupled into the drain through an inductor or a
    tank. So at max swing the actual drain voltage goes to 2xVcc. When the
    RF data sheets say "abs max" they mean the supply voltage.

    And they assume (without saying so) that the signal is RF or telecom,
    namely AC coupled and DC balanced. 8b10b or some such.

    So for pulse work, one throws away all that silly S-parameter and dBm >nonsense. I have a possibly new way to bias the HMC parts for
    electro-optical use; park high, pulse low.

    I wonder what sorts of philosophies various companies have when
    writing data sheet abs max specs.

    My impression is that use cases are the main driver.

    Joe

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From legg@21:1/5 to john larkin on Sat Oct 5 23:39:55 2024
    On Sat, 05 Oct 2024 11:38:35 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 19:18:15 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sat, 05 Oct 2024 08:03:14 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 06:45:40 GMT, Jan Panteltje <alien@comet.invalid> >>>wrote:

    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin >>>><JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>>>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    I know people who are terrified of running parts anywhere near abs
    max. I run some parts at 2x abs max voltage or power. Pushing parts is >>>the way to get performance, especially speed. Some work fine at 4x.

    Test them, blow up a few, define your own abs max. But only when there
    is a big payoff.

    I'm pushing a lot of HMC659's (15 GHz distributed amplifiers) to about
    2x voltage. It's intimidating to test them to destruction because they >>>cost over $300 each.

    Surely you are shortening the service life of those components by
    doing this. Just because they survive 24 hours or whatever at 4x
    voltage doesn't tell you everything. They might go 'pop' after a week
    or they might last a year. Either way, it's not good for repeat
    business?

    We have over a century of unit time so far and no problems.

    RF parts have terrible time-domain specs. The datasheets assume that
    the supply voltage is coupled into the drain through an inductor or a
    tank. So at max swing the actual drain voltage goes to 2xVcc. When the
    RF data sheets say "abs max" they mean the supply voltage.

    And they assume (without saying so) that the signal is RF or telecom,
    namely AC coupled and DC balanced. 8b10b or some such.

    So for pulse work, one throws away all that silly S-parameter and dBm >nonsense. I have a possibly new way to bias the HMC parts for
    electro-optical use; park high, pulse low.

    I wonder what sorts of philosophies various companies have when
    writing data sheet abs max specs.

    Pulse testing at low duty cycle is standard practise in a low
    thermal capacity test environment. Semiconductors and optical
    devices are typical subjects.

    Some longer term reliability information is extractible.

    https://epc-co.com/epc/DesignSupport/eGaNFETReliability/ReliabilityReportPhase14.aspx

    https://epc-co.com/epc/documents/product-training/Reliability%20Report%20Phase%2014.pdf

    RL

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to legg on Sat Oct 5 21:40:19 2024
    On Sat, 05 Oct 2024 23:39:55 -0400, legg <legg@nospam.magma.ca> wrote:

    On Sat, 05 Oct 2024 11:38:35 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 19:18:15 +0100, Cursitor Doom <cd@notformail.com> >>wrote:

    On Sat, 05 Oct 2024 08:03:14 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 06:45:40 GMT, Jan Panteltje <alien@comet.invalid> >>>>wrote:

    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin >>>>><JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>>>>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>>>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>>
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a >>>>>>>>>current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>>>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>>>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    I know people who are terrified of running parts anywhere near abs
    max. I run some parts at 2x abs max voltage or power. Pushing parts is >>>>the way to get performance, especially speed. Some work fine at 4x.

    Test them, blow up a few, define your own abs max. But only when there >>>>is a big payoff.

    I'm pushing a lot of HMC659's (15 GHz distributed amplifiers) to about >>>>2x voltage. It's intimidating to test them to destruction because they >>>>cost over $300 each.

    Surely you are shortening the service life of those components by
    doing this. Just because they survive 24 hours or whatever at 4x
    voltage doesn't tell you everything. They might go 'pop' after a week
    or they might last a year. Either way, it's not good for repeat
    business?

    We have over a century of unit time so far and no problems.

    RF parts have terrible time-domain specs. The datasheets assume that
    the supply voltage is coupled into the drain through an inductor or a
    tank. So at max swing the actual drain voltage goes to 2xVcc. When the
    RF data sheets say "abs max" they mean the supply voltage.

    And they assume (without saying so) that the signal is RF or telecom, >>namely AC coupled and DC balanced. 8b10b or some such.

    So for pulse work, one throws away all that silly S-parameter and dBm >>nonsense. I have a possibly new way to bias the HMC parts for >>electro-optical use; park high, pulse low.

    I wonder what sorts of philosophies various companies have when
    writing data sheet abs max specs.

    Pulse testing at low duty cycle is standard practise in a low
    thermal capacity test environment. Semiconductors and optical
    devices are typical subjects.

    Some longer term reliability information is extractible.

    https://epc-co.com/epc/DesignSupport/eGaNFETReliability/ReliabilityReportPhase14.aspx

    https://epc-co.com/epc/documents/product-training/Reliability%20Report%20Phase%2014.pdf

    RL

    The EPCs that I tried sort of zener at drain voltages around 2x
    specified abs max. Short-term at least, it's not destructive.

    Something weird happens to the gate if it's held above +6 or so for
    long. It gets leaky and the threshold changes. But it still works.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From legg@21:1/5 to john larkin on Sun Oct 6 12:37:29 2024
    On Sat, 05 Oct 2024 21:40:19 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 23:39:55 -0400, legg <legg@nospam.magma.ca> wrote:

    On Sat, 05 Oct 2024 11:38:35 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 19:18:15 +0100, Cursitor Doom <cd@notformail.com> >>>wrote:

    On Sat, 05 Oct 2024 08:03:14 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 06:45:40 GMT, Jan Panteltje <alien@comet.invalid> >>>>>wrote:

    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin >>>>>><JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>: >>>>>>
    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>>>>>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>>>>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>>>
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>>>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>>>>>joules. Freeze spray let it go back up to 100 volts or so. >>>>>>>>>>>
    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a >>>>>>>>>>current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly >>>>>>>>>>erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>>>>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>>>>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    I know people who are terrified of running parts anywhere near abs >>>>>max. I run some parts at 2x abs max voltage or power. Pushing parts is >>>>>the way to get performance, especially speed. Some work fine at 4x.

    Test them, blow up a few, define your own abs max. But only when there >>>>>is a big payoff.

    I'm pushing a lot of HMC659's (15 GHz distributed amplifiers) to about >>>>>2x voltage. It's intimidating to test them to destruction because they >>>>>cost over $300 each.

    Surely you are shortening the service life of those components by
    doing this. Just because they survive 24 hours or whatever at 4x >>>>voltage doesn't tell you everything. They might go 'pop' after a week >>>>or they might last a year. Either way, it's not good for repeat >>>>business?

    We have over a century of unit time so far and no problems.

    RF parts have terrible time-domain specs. The datasheets assume that
    the supply voltage is coupled into the drain through an inductor or a >>>tank. So at max swing the actual drain voltage goes to 2xVcc. When the
    RF data sheets say "abs max" they mean the supply voltage.

    And they assume (without saying so) that the signal is RF or telecom, >>>namely AC coupled and DC balanced. 8b10b or some such.

    So for pulse work, one throws away all that silly S-parameter and dBm >>>nonsense. I have a possibly new way to bias the HMC parts for >>>electro-optical use; park high, pulse low.

    I wonder what sorts of philosophies various companies have when
    writing data sheet abs max specs.

    Pulse testing at low duty cycle is standard practise in a low
    thermal capacity test environment. Semiconductors and optical
    devices are typical subjects.

    Some longer term reliability information is extractible.
    https://epc-co.com/epc/DesignSupport/eGaNFETReliability/ReliabilityReportPhase14.aspx
    https://epc-co.com/epc/documents/product-training/Reliability%20Report%20Phase%2014.pdf

    RL

    The EPCs that I tried sort of zener at drain voltages around 2x
    specified abs max. Short-term at least, it's not destructive.

    Something weird happens to the gate if it's held above +6 or so for
    long. It gets leaky and the threshold changes. But it still works.

    Read and comprehend.

    Enough articles stored serve as as a reference, next time you
    wonder 'what happens if I do that?'.

    RL

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to legg on Sun Oct 6 10:35:04 2024
    On Sun, 06 Oct 2024 12:37:29 -0400, legg <legg@nospam.magma.ca> wrote:

    On Sat, 05 Oct 2024 21:40:19 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 23:39:55 -0400, legg <legg@nospam.magma.ca> wrote:

    On Sat, 05 Oct 2024 11:38:35 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 19:18:15 +0100, Cursitor Doom <cd@notformail.com> >>>>wrote:

    On Sat, 05 Oct 2024 08:03:14 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 06:45:40 GMT, Jan Panteltje <alien@comet.invalid> >>>>>>wrote:

    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin >>>>>>><JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>: >>>>>>>
    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>>>>>>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>>>>>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>>>>>>>cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>>>>>>joules. Freeze spray let it go back up to 100 volts or so. >>>>>>>>>>>>
    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a >>>>>>>>>>>current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly >>>>>>>>>>>erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer
    to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>>>>>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings. >>>>>>>
    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    I know people who are terrified of running parts anywhere near abs >>>>>>max. I run some parts at 2x abs max voltage or power. Pushing parts is >>>>>>the way to get performance, especially speed. Some work fine at 4x. >>>>>>
    Test them, blow up a few, define your own abs max. But only when there >>>>>>is a big payoff.

    I'm pushing a lot of HMC659's (15 GHz distributed amplifiers) to about >>>>>>2x voltage. It's intimidating to test them to destruction because they >>>>>>cost over $300 each.

    Surely you are shortening the service life of those components by >>>>>doing this. Just because they survive 24 hours or whatever at 4x >>>>>voltage doesn't tell you everything. They might go 'pop' after a week >>>>>or they might last a year. Either way, it's not good for repeat >>>>>business?

    We have over a century of unit time so far and no problems.

    RF parts have terrible time-domain specs. The datasheets assume that >>>>the supply voltage is coupled into the drain through an inductor or a >>>>tank. So at max swing the actual drain voltage goes to 2xVcc. When the >>>>RF data sheets say "abs max" they mean the supply voltage.

    And they assume (without saying so) that the signal is RF or telecom, >>>>namely AC coupled and DC balanced. 8b10b or some such.

    So for pulse work, one throws away all that silly S-parameter and dBm >>>>nonsense. I have a possibly new way to bias the HMC parts for >>>>electro-optical use; park high, pulse low.

    I wonder what sorts of philosophies various companies have when
    writing data sheet abs max specs.

    Pulse testing at low duty cycle is standard practise in a low
    thermal capacity test environment. Semiconductors and optical
    devices are typical subjects.

    Some longer term reliability information is extractible.
    https://epc-co.com/epc/DesignSupport/eGaNFETReliability/ReliabilityReportPhase14.aspx
    https://epc-co.com/epc/documents/product-training/Reliability%20Report%20Phase%2014.pdf

    RL

    The EPCs that I tried sort of zener at drain voltages around 2x
    specified abs max. Short-term at least, it's not destructive.

    Something weird happens to the gate if it's held above +6 or so for
    long. It gets leaky and the threshold changes. But it still works.

    Read and comprehend.

    Test and learn. But yes, typing is easier than soldering and
    measuring.


    Enough articles stored serve as as a reference, next time you
    wonder 'what happens if I do that?'.


    For some odd reason, parts makers don't confess all the quirks and
    failure modes of their parts on the data sheets. Most actually hide
    them.

    What are the quirkiest parts? Analog multiplexers?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Mon Oct 7 16:39:27 2024
    On 7/10/2024 4:35 am, john larkin wrote:
    On Sun, 06 Oct 2024 12:37:29 -0400, legg <legg@nospam.magma.ca> wrote:

    On Sat, 05 Oct 2024 21:40:19 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 23:39:55 -0400, legg <legg@nospam.magma.ca> wrote:

    On Sat, 05 Oct 2024 11:38:35 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 19:18:15 +0100, Cursitor Doom <cd@notformail.com> >>>>> wrote:

    On Sat, 05 Oct 2024 08:03:14 -0700, john larkin <JL@gct.com> wrote: >>>>>>
    On Sat, 05 Oct 2024 06:45:40 GMT, Jan Panteltje <alien@comet.invalid> >>>>>>> wrote:

    On a sunny day (Fri, 04 Oct 2024 22:15:50 -0700) it happened john larkin
    <JL@gct.com> wrote in <8qi1gj5d27uqdkudv6vfql0fcv273mjcve@4ax.com>: >>>>>>>>
    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>>>>>>> wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote:

    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com>
    wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and
    cranked up the voltage. It started drawing a bunch of current at 105
    volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>>>>>>> joules. Freeze spray let it go back up to 100 volts or so. >>>>>>>>>>>>>
    None of that seemed to damage it, so an electrolytic cap sort of has a
    built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a >>>>>>>>>>>> current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer
    to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>>>>>>> out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings. >>>>>>>>
    How do you know, have you been once?

    BTW I did test some parts out of spec..
    But many problems come from aging with electrolytic caps.
    My old Samsung TV lasted 20 years... on many hours a day.
    So good electrolytics do exist.
    Just designing a bit below maximum specs may help.

    I know people who are terrified of running parts anywhere near abs >>>>>>> max. I run some parts at 2x abs max voltage or power. Pushing parts is >>>>>>> the way to get performance, especially speed. Some work fine at 4x. >>>>>>>
    Test them, blow up a few, define your own abs max. But only when there >>>>>>> is a big payoff.

    I'm pushing a lot of HMC659's (15 GHz distributed amplifiers) to about >>>>>>> 2x voltage. It's intimidating to test them to destruction because they >>>>>>> cost over $300 each.

    Surely you are shortening the service life of those components by
    doing this. Just because they survive 24 hours or whatever at 4x
    voltage doesn't tell you everything. They might go 'pop' after a week >>>>>> or they might last a year. Either way, it's not good for repeat
    business?

    We have over a century of unit time so far and no problems.

    RF parts have terrible time-domain specs. The datasheets assume that >>>>> the supply voltage is coupled into the drain through an inductor or a >>>>> tank. So at max swing the actual drain voltage goes to 2xVcc. When the >>>>> RF data sheets say "abs max" they mean the supply voltage.

    And they assume (without saying so) that the signal is RF or telecom, >>>>> namely AC coupled and DC balanced. 8b10b or some such.

    So for pulse work, one throws away all that silly S-parameter and dBm >>>>> nonsense. I have a possibly new way to bias the HMC parts for
    electro-optical use; park high, pulse low.

    I wonder what sorts of philosophies various companies have when
    writing data sheet abs max specs.

    Pulse testing at low duty cycle is standard practise in a low
    thermal capacity test environment. Semiconductors and optical
    devices are typical subjects.

    Some longer term reliability information is extractible.

    https://epc-co.com/epc/DesignSupport/eGaNFETReliability/ReliabilityReportPhase14.aspx

    https://epc-co.com/epc/documents/product-training/Reliability%20Report%20Phase%2014.pdf

    RL

    The EPCs that I tried sort of zener at drain voltages around 2x
    specified abs max. Short-term at least, it's not destructive.

    Something weird happens to the gate if it's held above +6 or so for
    long. It gets leaky and the threshold changes. But it still works.

    Read and comprehend.

    Test and learn. But yes, typing is easier than soldering and
    measuring.

    And careful reading should be easier than either, if you can manage it.

    Enough articles stored serve as as a reference, next time you
    wonder 'what happens if I do that?'.


    For some odd reason, parts makers don't confess all the quirks and
    failure modes of their parts on the data sheets. Most actually hide
    them.

    They never emphasise them, but their lawyers usually insist that they
    cover them, at least in obscure foot-notes and small print. Once long
    data sheets became practical (after the world wide web got popular) even
    Texas Instruments started publishing informative data sheets, but the
    bad news did show up in the last pages.

    What are the quirkiest parts? Analog multiplexers?

    Rail-to-rail op amps can be pretty odd.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin@21:1/5 to All on Mon Oct 7 10:33:21 2024
    On Sat, 05 Oct 2024 22:36:47 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sat, 05 Oct 2024 11:41:23 -0700, john larkin <JL@gct.com> wrote:

    On Sat, 05 Oct 2024 19:14:04 +0100, Cursitor Doom <cd@notformail.com> >>wrote:

    On Fri, 04 Oct 2024 22:15:50 -0700, john larkin <JL@gct.com> wrote:

    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>>wrote:

    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>>wrote:

    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>
    On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>>>wrote:

    I got a small (under 1" long) aluminum electro cap, 220 uF 63v, and >>>>>>>>cranked up the voltage. It started drawing a bunch of current at 105 >>>>>>>>volts, got hot, and folded back to 80 mA at 87v.

    It got too hot to touch in a couple of minutes, after roughly 500 >>>>>>>>joules. Freeze spray let it go back up to 100 volts or so.

    None of that seemed to damage it, so an electrolytic cap sort of has a >>>>>>>>built-in MOV.

    You're not 'heating a cap'.

    Felt hot to me.


    You're applying voltage overstress to failure, using a
    current limited source.

    But it didn't fail.


    This tells you precisely nothing.

    Told me a lot. Why elect to not learn things?


    Were you earing safety glasses?

    No earrings, and my normal glasses.


    Are you sure you want to advertize this increasingly
    erratic behavior?

    Experimenting with parts is admittedly a bizarre thing for an engineer >>>>>>to do. Sorry.

    Legg seems to have a problem on the groups with anyone who isn't an >>>>>out-and-out Commie. Just ignore him.

    There's no reason to not destroy parts. They don't have feelings.

    Well, personally speaking, I've derived a great deal of satisfaction >>>from doing so over the years.

    Yes, especially when loud bangs and smoke are involved.
    https://www.dropbox.com/scl/fi/oq1bgzkpsdcsmrg63w1r9/ExFets.jpg?rlkey=jcscvg5vt1qebgyxb0gt5575q&raw=1

    Hmm. Electrolytics still give the best bang-per-buck. And the great
    thing is, if they're old and fucked, they still give a great *bang* so
    you don't need to waste costly new parts.

    It's new available parts that we want to test. Those were
    switching-type mosfets used in kilowatt analog modes, in NMR gradient
    coil drivers. We picked the best.

    Most switchmode fets really don't like to see much current and much
    voltage simultaneously.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Tue Oct 8 15:43:22 2024
    On 8/10/2024 4:33 am, john larkin wrote:
    On Sat, 05 Oct 2024 22:36:47 +0100, Cursitor Doom <cd@notformail.com>
    wrote:
    On Sat, 05 Oct 2024 11:41:23 -0700, john larkin <JL@gct.com> wrote:
    On Sat, 05 Oct 2024 19:14:04 +0100, Cursitor Doom <cd@notformail.com>
    wrote:
    On Fri, 04 Oct 2024 22:15:50 -0700, john larkin <JL@gct.com> wrote:
    On Fri, 04 Oct 2024 23:50:36 +0100, Cursitor Doom <cd@notformail.com> >>>>> wrote:
    On Fri, 04 Oct 2024 10:31:13 -0700, john larkin <jl@glen--canyon.com> >>>>>> wrote:
    On Fri, 04 Oct 2024 12:10:38 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>> On Thu, 03 Oct 2024 16:36:24 -0700, john larkin <jl@glen--canyon.com> >>>>>>>> wrote:

    <snip>

    Well, personally speaking, I've derived a great deal of satisfaction
    from doing so over the years.

    Yes, especially when loud bangs and smoke are involved.

    https://www.dropbox.com/scl/fi/oq1bgzkpsdcsmrg63w1r9/ExFets.jpg?rlkey=jcscvg5vt1qebgyxb0gt5575q&raw=1

    Hmm. Electrolytics still give the best bang-per-buck. And the great
    thing is, if they're old and fucked, they still give a great *bang* so
    you don't need to waste costly new parts.

    It's new available parts that we want to test. Those were
    switching-type mosfets used in kilowatt analog modes, in NMR gradient
    coil drivers. We picked the best.

    Most switchmode fets really don't like to see much current and much
    voltage simultaneously.

    Lots of current at lots of volts is lots of watts being dissipated in
    the fet. Circuit designers generally try to avoid that.

    In analog mode, you can't, and you need specialised devices that can
    dissipate a lot of power. John Larkin doesn't have that point of view -
    his "the best" is what is best at doing what he wants done.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)