Re: discharging caps

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Sujet : Re: discharging caps
De : jl (at) *nospam* glen--canyon.com (john larkin)
Groupes : sci.electronics.design
Date : 16. Sep 2026, 11:21:47
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <eiqkal111otd7c5e6jf6vgkkn5tq6str5l@4ax.com>
References : 1 2 3 4 5 6 7 8 9 10 11 12
User-Agent : ForteAgent/8.00.32.1272
On Wed, 16 Sep 2026 18:39:28 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:

On 16/09/2026 3:23 am, john larkin wrote:
On Tue, 15 Sep 2026 18:28:40 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
 
On 15/09/2026 1:21 am, john larkin wrote:
On Mon, 14 Sep 2026 16:05:43 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
>
On 14/09/2026 10:12 am, john larkin wrote:
On Sun, 13 Sep 2026 23:54:47 +0100, Simon Simple
<nothanks@nottoday.co.uk> wrote:
>
On 13/09/2026 20:03, john larkin wrote:
>
<xxxx>>
130 KG is a lot of stuff.
>
130 kelvin gauss?
>
Don't be silly. The measurement is obviously in kangaroo gibongs.
Kangaroo's I've seen. "Gibongs" apears to be a nonsense word.
>
Nobody could ever accuse you of attempting humor.
>
Not that you've noticed. If you were trying to be funny, you didn't make it.
>
My guess is that John Larin meant kilograms, for which the usual
abbreviation is kgm, not KG.
>
gm? What's a gm? Transconductance?
>
American physics courses don't seem to have been big on System
International (SI) units when young Larkin was young and somewhat
susceptible to education.
 
https://en.wikipedia.org/wiki/Gram
 
The unit is  g  not  gm.
 
>
Engineers benefit from quickly discounting designs that are orders of
magnitude away from being sensible.
>
Lazy engineers save their brains from excessive effort by telling
themselves that. It isn't always true, but john Larkin lies to himself
about that too.
>
130 kilograms of inductor is clearly absurd by about 4 orders of
magnitude.  A few seconds of mental calculation dismisses the inductor
idea. [1]
>
Besides the quantitative absurdity, depletion fets are smaller and
cheaper than inductors, and surface mount. DN2530 costs us 43 cents.
>
https://www.mouser.com/datasheet/2/391/DN2530-36932.pdf?srsltid=AfmBOorXOdCkWEQBmjqXp5tGJIUvVC5VAQqugUbHjdpvBszaeReYJDUP
>
It's tiny. You really don't want it to carry  more than 300mA (even
briefly) and you need to bias the gate about 10V below the source to
keep it off. It may be a practicable solution, but it won't be a simple one.
 
I posted my discharge circuit. It's simple. And the DN2530 pinches off
around -2 volts.
 
When you were in school, didn't they teach you to check your work?
>
You need more than -2V for a proper pinch-off. I check my work to my
pown standards, not yours.

And your spelling, too.

>
Design a better discharge circuit, with values, and we can discuss it.
>
[1] I'm sort of known for doing math like this standing up at a
whiteboard. There are actually tricks, known as "lightning empiricism"
>
Jim Wiliams' 1991 book has a section on that.
>
John Larkin is better known for his skills in self-congratulation.
 
No, I let other people do that.
>
But you do make it clear that if they don't do it they will end up being
accused of being negative and insulting.

Most of your posts are coarse insults.

>
And  "I'm sort of known for doing math like this standing up at a
whiteboard" does look remarkably like self-congratulation.

As noted, "lightning empiricism" is handy, and not especially
difficult.

I was recently sitting in on a class at CCSF and the prof was
lecturing about a circuit. He said "the current is 6 divided by 0.05.
Does anbody know what that is? Nobody did, so I said "120" and he said
"thank you". None of the maybe 30 kids in the room could do the math
in their heads. It's two simple steps.


John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics

Date Sujet#  Auteur
7 Sep 26 * discharging caps162john larkin
7 Sep 26 +* Re: discharging caps7Simon Simple
7 Sep 26 i`* Re: discharging caps6john larkin
7 Sep 26 i +- Re: discharging caps1Simon Simple
8 Sep 26 i `* Re: discharging caps4legg
8 Sep 26 i  +- Re: discharging caps1john larkin
8 Sep 26 i  `* Re: discharging caps2Phil Hobbs
8 Sep 26 i   `- Re: discharging caps1john larkin
7 Sep 26 +* Re: discharging caps12ehsjr
7 Sep 26 i`* Re: discharging caps11john larkin
7 Sep 26 i +* Re: discharging caps2Liz Tuddenham
7 Sep 26 i i`- Re: discharging caps1john larkin
8 Sep 26 i `* Re: discharging caps8Jan Panteltje
8 Sep 26 i  `* Re: discharging caps7john larkin
8 Sep 26 i   `* Re: discharging caps6Jan Panteltje
8 Sep 26 i    `* Re: discharging caps5john larkin
9 Sep 26 i     `* Re: discharging caps4Jan Panteltje
11 Sep11:54 i      `* Re: discharging caps3Simon Simple
11 Sep12:01 i       +- Re: discharging caps1Jan Panteltje
11 Sep14:59 i       `- Re: discharging caps1Phil Hobbs
7 Sep 26 +* Re: discharging caps2Bill Sloman
7 Sep 26 i`- Re: discharging caps1john larkin
7 Sep 26 +* Re: discharging caps87chrisq
7 Sep 26 i+* Re: discharging caps84john larkin
8 Sep 26 ii+* Re: discharging caps62Bill Sloman
8 Sep 26 iii+* Re: discharging caps4john larkin
8 Sep 26 iiii`* Re: discharging caps3Bill Sloman
8 Sep 26 iiii `* Re: discharging caps2john larkin
9 Sep 26 iiii  `- Re: discharging caps1Bill Sloman
8 Sep 26 iii`* Re: discharging caps57john larkin
8 Sep 26 iii `* Re: discharging caps56Bill Sloman
8 Sep 26 iii  `* Re: discharging caps55john larkin
9 Sep 26 iii   `* Re: discharging caps54Bill Sloman
9 Sep 26 iii    `* Re: discharging caps53piglet
9 Sep 26 iii     `* Re: discharging caps52john larkin
9 Sep 26 iii      +- Re: discharging caps1Bill Sloman
9 Sep 26 iii      `* Re: discharging caps50Jeroen Belleman
9 Sep 26 iii       +* Re: discharging caps9Bill Sloman
9 Sep 26 iii       i+* Re: discharging caps6john larkin
9 Sep 26 iii       ii`* Re: discharging caps5Bill Sloman
9 Sep 26 iii       ii `* Re: discharging caps4john larkin
10 Sep 26 iii       ii  `* Re: discharging caps3Bill Sloman
10 Sep 26 iii       ii   `* Re: discharging caps2john larkin
10 Sep 26 iii       ii    `- Re: discharging caps1Bill Sloman
9 Sep 26 iii       i`* Re: discharging caps2chrisq
9 Sep 26 iii       i `- Re: discharging caps1Bill Sloman
9 Sep 26 iii       `* Re: discharging caps40Bill Sloman
9 Sep 26 iii        +* Re: discharging caps37Jeroen Belleman
10 Sep 26 iii        i`* Re: discharging caps36Bill Sloman
13 Sep01:27 iii        i `* Re: discharging caps35Waldek Hebisch
13 Sep01:38 iii        i  +* Re: discharging caps20Lane W
13 Sep04:11 iii        i  i`* Re: discharging caps19Waldek Hebisch
13 Sep15:50 iii        i  i `* Re: discharging caps18john larkin
13 Sep16:14 iii        i  i  +* Re: discharging caps3Lane W
13 Sep17:18 iii        i  i  i`* Re: discharging caps2Bill Sloman
13 Sep17:28 iii        i  i  i `- Re: discharging caps1Lane W
13 Sep16:28 iii        i  i  `* Re: discharging caps14Bill Sloman
13 Sep20:03 iii        i  i   `* Re: discharging caps13john larkin
13 Sep23:54 iii        i  i    +* Re: discharging caps9Simon Simple
14 Sep01:12 iii        i  i    i`* Re: discharging caps8john larkin
14 Sep07:05 iii        i  i    i `* Re: discharging caps7Bill Sloman
14 Sep16:21 iii        i  i    i  `* Re: discharging caps6john larkin
15 Sep09:28 iii        i  i    i   `* Re: discharging caps5Bill Sloman
15 Sep18:23 iii        i  i    i    `* Re: discharging caps4john larkin
16 Sep09:39 iii        i  i    i     `* Re: discharging caps3Bill Sloman
16 Sep11:21 iii        i  i    i      `* Re: discharging caps2john larkin
16 Sep12:16 iii        i  i    i       `- Re: discharging caps1Bill Sloman
14 Sep06:59 iii        i  i    `* Re: discharging caps3Bill Sloman
14 Sep16:22 iii        i  i     `* Re: discharging caps2john larkin
15 Sep09:31 iii        i  i      `- Re: discharging caps1Bill Sloman
13 Sep01:59 iii        i  +* Re: discharging caps3john larkin
13 Sep05:21 iii        i  i+- Re: discharging caps1wmartin
13 Sep07:27 iii        i  i`- Re: discharging caps1Bill Sloman
13 Sep07:24 iii        i  `* Re: discharging caps11Bill Sloman
13 Sep14:36 iii        i   `* Re: discharging caps10Waldek Hebisch
13 Sep17:05 iii        i    `* Re: discharging caps9Bill Sloman
13 Sep19:40 iii        i     `* Re: discharging caps8John R Walliker
13 Sep20:08 iii        i      +* Re: discharging caps4john larkin
14 Sep07:18 iii        i      i`* Re: discharging caps3Bill Sloman
14 Sep16:24 iii        i      i `* Re: discharging caps2john larkin
15 Sep09:36 iii        i      i  `- Re: discharging caps1Bill Sloman
14 Sep07:11 iii        i      `* Re: discharging caps3Bill Sloman
14 Sep16:56 iii        i       `* Re: discharging caps2john larkin
15 Sep09:50 iii        i        `- Re: discharging caps1Bill Sloman
10 Sep 26 iii        `* Re: discharging caps2john larkin
10 Sep 26 iii         `- Re: discharging caps1Bill Sloman
8 Sep 26 ii+* Re: discharging caps14chrisq
8 Sep 26 iii+- Re: discharging caps1chrisq
8 Sep 26 iii`* Re: discharging caps12john larkin
8 Sep 26 iii +* Re: discharging caps3chrisq
8 Sep 26 iii i`* Re: discharging caps2chrisq
9 Sep 26 iii i `- Re: discharging caps1john larkin
8 Sep 26 iii +* Re: discharging caps5Bill Sloman
8 Sep 26 iii i`* Re: discharging caps4john larkin
9 Sep 26 iii i `* Re: discharging caps3Bill Sloman
9 Sep 26 iii i  `* Re: discharging caps2john larkin
9 Sep 26 iii i   `- Re: discharging caps1Bill Sloman
8 Sep 26 iii +- Re: discharging caps1Bill Sloman
14 Sep17:44 iii `* Re: discharging caps2Buzz McCool
14 Sep18:15 iii  `- Re: discharging caps1john larkin
11 Sep07:23 ii+* Re: discharging caps3Bill Sloman
17 Sep08:19 ii`* Re: discharging caps4Cydrome Leader
8 Sep 26 i`* Re: discharging caps2Jan Panteltje
7 Sep 26 +* Re: discharging caps20Lasse Langwadt
8 Sep 26 +- Re: discharging caps1legg
9 Sep 26 +- Re: discharging caps1Jeremiah Jones
9 Sep 26 +* Re: discharging caps17someone
9 Sep 26 +* Re: discharging caps6Joerg
13 Sep19:52 `* Re: discharging caps8legg

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