Sujet : Re: heating a cap
De : jl (at) *nospam* glen--canyon.com (john larkin)
Groupes : sci.electronics.designDate : 07. Oct 2024, 18:33:21
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <al68gjlf9d4hhcd5rph38tre2e4ve2f1le@4ax.com>
References : 1 2 3 4 5 6 7 8
User-Agent : ForteAgent/8.00.32.1272
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.
heating a cap
Re: heating a cap
