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.
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.
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 ;-#)#
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.
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.
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.
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.
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
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.
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!
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
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.
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.
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.
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 electrolytics start to leak seriously at about 1.5x rated voltage and die from overheating.
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.
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
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
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.
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.
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.
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.
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?
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
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.
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.
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
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.
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:How do you know, have you been once?
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. >>>>>>>
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?'.
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:How do you know, have you been once?
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. >>>>>>>>
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?
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.
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:
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.
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