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Groups > sci.electronics.design > #747328 > unrolled thread
| Started by | john larkin <jl@glen--canyon.com> |
|---|---|
| First post | 2026-09-07 08:18 -0700 |
| Last post | 2026-09-26 10:25 -0400 |
| Articles | 20 on this page of 259 — 26 participants |
Back to article view | Back to sci.electronics.design
discharging caps john larkin <jl@glen--canyon.com> - 2026-09-07 08:18 -0700
Re: discharging caps Simon Simple <nothanks@nottoday.co.uk> - 2026-09-07 17:20 +0100
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-07 09:58 -0700
Re: discharging caps Simon Simple <nothanks@nottoday.co.uk> - 2026-09-07 19:51 +0100
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-08 10:27 -0400
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-08 08:16 -0700
Re: discharging caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-09-08 15:44 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-08 09:35 -0700
Re: discharging caps ehsjr <ehsjr@verizon.net> - 2026-09-07 12:26 -0400
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-07 10:00 -0700
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-07 19:32 +0100
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-07 15:38 -0700
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-08 07:41 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-08 07:57 -0700
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-08 15:23 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-08 09:38 -0700
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-09 10:33 +0000
Re: discharging caps Simon Simple <nothanks@nottoday.co.uk> - 2026-09-11 11:54 +0100
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-11 11:01 +0000
Re: discharging caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-09-11 13:59 +0000
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-08 04:28 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-07 11:59 -0700
Re: discharging caps chrisq <syseng@gfsys.co.uk> - 2026-09-07 19:33 +0100
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-07 11:52 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-08 17:35 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-08 07:43 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-09 02:03 +1000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-08 13:10 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-09 16:25 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-08 08:00 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-09 03:09 +1000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-08 12:56 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-09 16:40 +1000
Re: discharging caps piglet <erichpwagner@hotmail.com> - 2026-09-09 09:51 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-09 03:44 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-09 20:57 +1000
Re: discharging caps Jeroen Belleman <jeroen@nospam.please> - 2026-09-09 14:25 +0200
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-10 00:12 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-09 07:59 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-10 02:27 +1000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-09 10:42 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-10 17:43 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-10 07:10 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-11 00:58 +1000
Re: discharging caps chrisq <syseng@gfsys.co.uk> - 2026-09-09 17:29 +0100
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-10 03:35 +1000
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-10 01:32 +1000
Re: discharging caps Jeroen Belleman <jeroen@nospam.please> - 2026-09-09 23:10 +0200
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-10 18:38 +1000
Re: discharging caps antispam@fricas.org (Waldek Hebisch) - 2026-09-13 00:27 +0000
Re: discharging caps Lane W <cactus_DAC@yahoo.com> - 2026-09-12 18:38 -0600
Re: discharging caps antispam@fricas.org (Waldek Hebisch) - 2026-09-13 03:11 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-13 07:50 -0700
Re: discharging caps Lane W <cactus_DAC@yahoo.com> - 2026-09-13 09:14 -0600
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-14 02:18 +1000
Re: discharging caps Lane W <cactus_DAC@yahoo.com> - 2026-09-13 10:28 -0600
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-14 01:28 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-13 12:03 -0700
Re: discharging caps Simon Simple <nothanks@nottoday.co.uk> - 2026-09-13 23:54 +0100
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-13 17:12 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-14 16:05 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-14 08:21 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-15 18:28 +1000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-15 10:23 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-16 18:39 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-16 03:21 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-16 21:16 +1000
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-14 15:59 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-14 08:22 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-15 18:31 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-12 17:59 -0700
Re: discharging caps wmartin <wwm@wwmartin.net> - 2026-09-12 21:21 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-13 16:27 +1000
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-13 16:24 +1000
Re: discharging caps antispam@fricas.org (Waldek Hebisch) - 2026-09-13 13:36 +0000
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-14 02:05 +1000
Re: discharging caps John R Walliker <jrwalliker@gmail.com> - 2026-09-13 19:40 +0100
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-13 12:08 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-14 16:18 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-14 08:24 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-15 18:36 +1000
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-14 16:11 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-14 08:56 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-15 18:50 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-10 07:17 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-11 01:02 +1000
Re: discharging caps chrisq <syseng@gfsys.co.uk> - 2026-09-08 11:19 +0100
Re: discharging caps chrisq <syseng@gfsys.co.uk> - 2026-09-08 11:33 +0100
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-08 07:23 -0700
Re: discharging caps chrisq <syseng@gfsys.co.uk> - 2026-09-08 16:28 +0100
Re: discharging caps chrisq <syseng@gfsys.co.uk> - 2026-09-08 21:13 +0100
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-08 16:06 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-09 02:10 +1000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-08 12:59 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-09 16:45 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-09 03:22 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-09 21:07 +1000
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-09 02:10 +1000
Re: discharging caps Buzz McCool <buzz_mccool@yahoo.com> - 2026-09-14 09:44 -0700
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-14 10:15 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-11 16:23 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-11 07:45 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-12 01:59 +1000
Re: discharging caps Cydrome Leader <presence@MUNGEpanix.com> - 2026-09-17 07:19 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-17 07:46 -0700
Re: discharging caps Cydrome Leader <presence@MUNGEpanix.com> - 2026-09-18 04:54 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-18 07:57 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-18 15:45 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-18 08:02 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-19 16:40 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-19 08:48 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-20 16:30 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-20 02:17 -0700
Re: discharging caps Simon Simple <nothanks@nottoday.co.uk> - 2026-09-20 12:30 +0100
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-21 00:52 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-20 08:46 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-21 17:41 +1000
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-08 07:46 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-08 07:26 -0700
Re: discharging caps Lasse Langwadt <llc@fonz.dk> - 2026-09-07 21:18 +0200
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-07 12:36 -0700
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-07 22:26 +0100
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-07 15:14 -0700
Re: discharging caps "Edward Rawde" <invalid@invalid.invalid> - 2026-09-07 20:06 -0400
Re: discharging caps Don Y <blockedofcourse@foo.invalid> - 2026-09-07 19:30 -0700
Re: discharging caps "Edward Rawde" <invalid@invalid.invalid> - 2026-09-07 23:40 -0400
Re: discharging caps Don Y <blockedofcourse@foo.invalid> - 2026-09-07 22:04 -0700
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-08 08:45 +0100
Re: discharging caps John R Walliker <jrwalliker@gmail.com> - 2026-09-08 11:59 +0100
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-08 12:30 +0100
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-08 07:34 -0700
Re: discharging caps ehsjr <ehsjr@verizon.net> - 2026-09-08 12:55 -0400
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-13 08:15 +0100
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-13 07:41 -0700
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-13 17:45 +0100
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-14 03:53 +1000
Re: discharging caps John R Walliker <jrwalliker@gmail.com> - 2026-09-13 19:28 +0100
Re: discharging caps ehsjr <ehsjr@verizon.net> - 2026-09-13 17:16 -0400
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-14 10:20 -0400
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-14 15:41 +0100
Re: discharging caps Carl <carl.ijamesXX@YYverizon.net> - 2026-09-07 21:10 -0400
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-08 10:37 -0400
Re: discharging caps Jeremiah Jones <jj@j.j> - 2026-09-08 22:14 -0700
Re: discharging caps someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> - 2026-09-09 17:45 +0000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-09 11:40 -0700
Re: discharging caps Simon Simple <nothanks@nottoday.co.uk> - 2026-09-10 09:55 +0100
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-10 07:20 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-11 16:32 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-11 07:46 -0700
Re: discharging caps Simon Simple <nothanks@nottoday.co.uk> - 2026-09-11 17:08 +0100
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-11 14:28 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-12 16:24 +1000
Re: discharging caps John R Walliker <jrwalliker@gmail.com> - 2026-09-12 10:49 +0100
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-13 01:09 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-12 07:54 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-13 01:20 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-12 09:12 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-13 02:53 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-12 12:43 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-13 16:37 +1000
Re: discharging caps Joerg <news@analogconsultants.com> - 2026-09-09 15:15 -0700
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-10 12:25 +0100
Re: discharging caps Simon Simple <nothanks@nottoday.co.uk> - 2026-09-10 13:09 +0100
Re: discharging caps John R Walliker <jrwalliker@gmail.com> - 2026-09-10 14:10 +0100
Re: discharging caps Joerg <news@analogconsultants.com> - 2026-09-10 11:05 -0700
Re: discharging caps Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-09-10 19:12 +0000
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-13 14:52 -0400
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-13 12:17 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-14 16:25 +1000
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-14 10:15 -0400
Re: discharging caps "Edward Rawde" <invalid@invalid.invalid> - 2026-09-17 19:53 -0400
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-17 19:15 -0700
Re: discharging caps "Edward Rawde" <invalid@invalid.invalid> - 2026-09-17 23:50 -0400
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-18 15:58 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-18 07:26 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-19 16:26 +1000
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-20 11:25 -0400
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-20 08:42 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-21 17:54 +1000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-21 10:09 -0700
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-21 08:59 -0400
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-21 08:02 -0700
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-21 13:00 -0400
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-21 10:12 -0700
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-22 10:12 -0400
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-22 08:25 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-23 03:55 +1000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-22 17:36 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-23 16:18 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-23 09:05 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-24 16:36 +1000
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-24 08:11 -0400
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-24 07:26 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-25 00:52 +1000
Re: discharging caps ehsjr <ehsjr@verizon.net> - 2026-09-24 18:40 -0400
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-24 16:22 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-25 16:50 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-25 07:26 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-26 01:32 +1000
Re: discharging caps antispam@fricas.org (Waldek Hebisch) - 2026-09-26 03:12 +0000
Re: discharging caps "Edward Rawde" <invalid@invalid.invalid> - 2026-09-26 00:38 -0400
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-26 07:08 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-27 01:07 +1000
Re: discharging caps JM <sunaecoNoChoppedPork@gmail.com> - 2026-09-26 15:49 +0100
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-28 10:11 -0700
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-23 09:24 -0400
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-21 17:01 +0000
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-20 11:44 -0400
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-23 21:42 +0100
Re: discharging caps Lane W <cactus_DAC@yahoo.com> - 2026-09-23 14:44 -0600
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-23 17:51 -0700
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-24 10:07 +0100
Re: discharging caps Simon Simple <nothanks@nottoday.co.uk> - 2026-09-24 12:01 +0100
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-24 13:59 +0100
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-23 14:16 -0700
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-24 10:07 +0100
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-24 11:51 -0700
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-24 07:58 -0400
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-24 07:54 -0400
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-24 13:59 +0100
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-24 17:56 -0400
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-24 16:27 -0700
Re: discharging caps liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-09-25 09:22 +0100
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-24 11:55 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-25 17:09 +1000
Re: discharging caps Jeroen Belleman <jeroen@nospam.please> - 2026-09-25 09:38 +0200
Re: discharging caps John R Walliker <jrwalliker@gmail.com> - 2026-09-25 10:59 +0100
Re: discharging caps Jeroen Belleman <jeroen@nospam.please> - 2026-09-25 12:28 +0200
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-25 22:42 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-25 07:38 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-26 01:11 +1000
Re: discharging caps Jeroen Belleman <jeroen@nospam.please> - 2026-09-25 19:59 +0200
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-26 15:56 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-26 09:24 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-27 16:22 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-27 03:20 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-27 20:55 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-27 07:59 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-28 12:35 +1000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-28 10:15 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-29 17:22 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-26 07:20 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-27 01:26 +1000
Re: discharging caps Jeroen Belleman <jeroen@nospam.please> - 2026-09-26 22:58 +0200
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-26 16:20 -0700
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-27 07:39 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-27 03:29 -0700
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-27 13:50 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-27 08:04 -0700
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-27 15:16 +0000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-27 08:29 -0700
Re: discharging caps Jan Panteltje <alien@comet.invalid> - 2026-09-28 06:38 +0000
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-28 17:34 +1000
Re: discharging caps john larkin <jl@htigct.com> - 2026-09-28 10:17 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-29 17:09 +1000
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-28 12:54 +1000
Re: discharging caps john larkin <jl@glen--canyon.com> - 2026-09-27 20:14 -0700
Re: discharging caps Bill Sloman <bill.sloman@ieee.org> - 2026-09-28 16:58 +1000
Re: discharging caps legg <legg@nospam.magma.ca> - 2026-09-26 10:25 -0400
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| From | Carl <carl.ijamesXX@YYverizon.net> |
|---|---|
| Date | 2026-09-07 21:10 -0400 |
| Message-ID | <rgJnS.2877$GL8e.2378@fx15.iad> |
| In reply to | #747328 |
On 9/7/26 11:18 AM, john larkin wrote: > Suppose we have a box with some big caps inside, for example 0.2 > farads that run at about 200 volts. When AC power is off, we want to > discharge them for several reasons. > > Putting, say, a 1K resistor across them dissipates 40 watts and has a > 200 second time constant. It will take many tau before the voltage > gets low enough for people to poke around inside. > > The ideal discharger would be a constant-current or even better a > constant-power load, all the way down to zero volts. It would be dumb, > not switched by some decision circuit or anything fancy like that. > > And of course we need several LEDs as warnings that the thing is hot. > > > John Larkin > Highland Tech Glen Canyon Design Center > Lunatic Fringe Electronics The traditional emergency discharge circuit for a supercon magnet like you used to make coil drivers for is two stud mounted diodes rated for the magnet current wired across from each other and mounted on a heatsink. Two diodes because you never know which way the last person to charge the thing connected the + and - leads :-). Switching was manual, of course, but it gave a constant power dump down to the diode cutoff. -- Regards, Carl
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| From | legg <legg@nospam.magma.ca> |
|---|---|
| Date | 2026-09-08 10:37 -0400 |
| Message-ID | <1770al9ndicoe0a24oma507rmem6i7me50@4ax.com> |
| In reply to | #747328 |
On Mon, 07 Sep 2026 08:18:22 -0700, john larkin <jl@glen--canyon.com> wrote: >Suppose we have a box with some big caps inside, for example 0.2 >farads that run at about 200 volts. When AC power is off, we want to >discharge them for several reasons. > >Putting, say, a 1K resistor across them dissipates 40 watts and has a >200 second time constant. It will take many tau before the voltage >gets low enough for people to poke around inside. > >The ideal discharger would be a constant-current or even better a >constant-power load, all the way down to zero volts. It would be dumb, >not switched by some decision circuit or anything fancy like that. > >And of course we need several LEDs as warnings that the thing is hot. > > >John Larkin >Highland Tech Glen Canyon Design Center >Lunatic Fringe Electronics The most common form of maintenance safety feature of high energy installations is a 'lock out' feature. This can be a simple hatch-activated switch that enforces various internal on/off features, such as motor de-energizing or energy storage discharge. Consult the relevant literature. RL
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| From | Jeremiah Jones <jj@j.j> |
|---|---|
| Date | 2026-09-08 22:14 -0700 |
| Message-ID | <a8q1aldqj3on2jd1v3mivgqg5cagdgafhm@4ax.com> |
| In reply to | #747328 |
john larkin <jl@glen--canyon.com> wrote: > Suppose we have a box with some big caps inside, for example 0.2 > farads that run at about 200 volts. When AC power is off, we want to > discharge them for several reasons. > > Putting, say, a 1K resistor across them dissipates 40 watts and has a > 200 second time constant. It will take many tau before the voltage > gets low enough for people to poke around inside. > > The ideal discharger would be a constant-current or even better a > constant-power load, all the way down to zero volts. It would be dumb, > not switched by some decision circuit or anything fancy like that. > > And of course we need several LEDs as warnings that the thing is hot. You only need an incandescent bulb, around 100 or 150 W, placed across the capacitor when you want to discharge it. It's cheap, low tech, high-power tolerant, has non-linear E/I curve in the right direction, and accomplishes the warning light part of the mission. 120vac bulbs might require two of them in series for 200+ volt dc use.
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| From | someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> |
|---|---|
| Date | 2026-09-09 17:45 +0000 |
| Message-ID | <18d3b81ac35dfcac$5733$2028749$4226dc73@news.newsgroupdirect.com> |
| In reply to | #747328 |
1/2CV^2 is 4,000J. 200 s discharge at constant power is 4,000/200= 20W , which is nothing. Cheapest way is Darlington current source driven by a multiplier error amp taking voltage input from the cap and current input from the Darlington emitter current sense. The multiplier only needs to be one quadrant, eliminating the need for that overpriced ripoff AD633 and its equivalents. That gives you three options: transconductance variable gain amp, digital PWM multiplier using something like 4066, or a log-antilog using a quad opamp LM324 type. The quad opamp should be the least trouble. There are plenty of circuits in the old NatSemi app notes, nothing extreme by way of diode matching is necessary for this application. When the voltage across the cap gets down to 10V, switch out the MOSFET and switch in a resistor. Current will be 2A by then. The constant power components should come in at under $10 (small quantity). Those linear MOSFETs are another major ripoff too, and bipolar is perfectly adequate for this purpose, and cheap. -- For full context, visit https://www.electrondepot.com/electrodesign/discharging-caps-4410124-.htm
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| From | john larkin <jl@htigct.com> |
|---|---|
| Date | 2026-09-09 11:40 -0700 |
| Message-ID | <ji93al5alshgodqv3ihnp8j3gsg8701a3b@4ax.com> |
| In reply to | #747506 |
On Wed, 09 Sep 2026 17:45:02 +0000, someone <2a59d59e3809f827ce709d3815e3950eef4a6a93af5557a93a7fdfba71460843@example.com> wrote: >1/2CV^2 is 4,000J. 200 s discharge at constant power is 4,000/200= 20W , which is nothing. > >Cheapest way is Darlington current source driven by a multiplier error amp taking voltage input from the cap and current input from the Darlington emitter current sense. The multiplier only needs to be one quadrant, eliminating the need for that overpriced ripoff AD633 and its equivalents. That gives you three options: transconductance variable gain amp, digital PWM multiplier using something like 4066, or a log-antilog using a quad opamp LM324 type. The quad opamp should be the least trouble. There are plenty of circuits in the old NatSemi app notes, nothing extreme by way of diode matching is necessary for this application. > >When the voltage across the cap gets down to 10V, switch out the MOSFET and switch in a resistor. Current will be 2A by then. > >The constant power components should come in at under $10 (small quantity). Those linear MOSFETs are another major ripoff too, and bipolar is perfectly adequate for this purpose, and cheap. We were thinking of doing the opposite: start with a power resistor and kick in a fet near the end of the discharge, to kill the exponential tail. We'd use several and leave them on all the time, which avoids a bunch of logic with its own failure modes. https://www.dropbox.com/scl/fi/w86g1m4si37dhadi9hw5u/P200_Discharge_1.jpg?rlkey=e1gyhxtivgjqzi85izlixk6sf&raw=1 Thanks for the ideas. It's helpful to get other peoples ideas.
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| From | Simon Simple <nothanks@nottoday.co.uk> |
|---|---|
| Date | 2026-09-10 09:55 +0100 |
| Message-ID | <117trat$1rets$1@dont-email.me> |
| In reply to | #747506 |
On 09/09/2026 18:45, someone wrote: > 1/2CV^2 is 4,000J. 200 s discharge at constant power is 4,000/200= > 20W , which is nothing. <xxxx> It's interesting. 4kJ would run my ordinary 3kW kettle for about 1.3 seconds and you'd not notice the water temperature rise, so therefore 4kJ is nothing much. But 4kJ would throw a 5kg bowling ball 160m (45 degrees, flat ground, no air, natch) which is a lot. -- SS
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-10 07:20 -0700 |
| Message-ID | <g0f5al185ifin5nvvcq22not9079s6hn90@4ax.com> |
| In reply to | #747530 |
On Thu, 10 Sep 2026 09:55:53 +0100, Simon Simple <nothanks@nottoday.co.uk> wrote: >On 09/09/2026 18:45, someone wrote: >> 1/2CV^2 is 4,000J. 200 s discharge at constant power is 4,000/200= >> 20W , which is nothing. ><xxxx> > >It's interesting. 4kJ would run my ordinary 3kW kettle for about 1.3 >seconds and you'd not notice the water temperature rise, so therefore >4kJ is nothing much. > >But 4kJ would throw a 5kg bowling ball 160m (45 degrees, flat ground, no >air, natch) which is a lot. 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. People would notice if that were shorted. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-11 16:32 +1000 |
| Message-ID | <118079g$2kpki$2@dont-email.me> |
| In reply to | #747539 |
On 11/09/2026 12:20 am, john larkin wrote: > On Thu, 10 Sep 2026 09:55:53 +0100, Simon Simple > <nothanks@nottoday.co.uk> wrote: > >> On 09/09/2026 18:45, someone wrote: >>> 1/2CV^2 is 4,000J. 200 s discharge at constant power is 4,000/200= >>> 20W , which is nothing. >> <xxxx> >> >> It's interesting. 4kJ would run my ordinary 3kW kettle for about 1.3 >> seconds and you'd not notice the water temperature rise, so therefore >> 4kJ is nothing much. >> >> But 4kJ would throw a 5kg bowling ball 160m (45 degrees, flat ground, no >> air, natch) which is a lot. > > 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. > > People would notice if that were shorted. Not if the energy were dissipated making the internals of a couple of big resistors several hundred degrees warmer for a few minutes. That isn't noisy or flashy. Capacitors don't change shape much when they discharge. The wiring around big inductors can move. Big transformers hum if the windings aren't impregnated, so making the discharge curve critically damped with an inductor might call for extra care. -- Bill Sloman, Sydney
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-11 07:46 -0700 |
| Message-ID | <1158allqkjm1jo5osrdqu3lndeshb8a0s3@4ax.com> |
| In reply to | #747564 |
On Fri, 11 Sep 2026 16:32:03 +1000, Bill Sloman <bill.sloman@ieee.org> wrote: >On 11/09/2026 12:20 am, john larkin wrote: >> On Thu, 10 Sep 2026 09:55:53 +0100, Simon Simple >> <nothanks@nottoday.co.uk> wrote: >> >>> On 09/09/2026 18:45, someone wrote: >>>> 1/2CV^2 is 4,000J. 200 s discharge at constant power is 4,000/200= >>>> 20W , which is nothing. >>> <xxxx> >>> >>> It's interesting. 4kJ would run my ordinary 3kW kettle for about 1.3 >>> seconds and you'd not notice the water temperature rise, so therefore >>> 4kJ is nothing much. >>> >>> But 4kJ would throw a 5kg bowling ball 160m (45 degrees, flat ground, no >>> air, natch) which is a lot. >> >> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >> >> People would notice if that were shorted. > >Not if the energy were dissipated making the internals of a couple of >big resistors several hundred degrees warmer for a few minutes. Did I remember to say "shorted" ? John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Simon Simple <nothanks@nottoday.co.uk> |
|---|---|
| Date | 2026-09-11 17:08 +0100 |
| Message-ID | <1181914$31p91$1@dont-email.me> |
| In reply to | #747539 |
On 10/09/2026 15:20, john larkin wrote: <xxxx>> > 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. If I've done the sums right, that's a capacitor bank bigger than six beer cans storing about the same energy as one AAA cell! > People would notice if that were shorted. Yes, I used to operate capacitor banks of maybe 2-4 times that physical size charged to 1kV and discharged via a spark gap through a marine sparker for seismic work. Long time ago before H&S was a thing. -- SS
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| From | john larkin <jl@htigct.com> |
|---|---|
| Date | 2026-09-11 14:28 -0700 |
| Message-ID | <cbs8alhspo1m1bl59ctt612bkdfqcuob13@4ax.com> |
| In reply to | #747582 |
On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple <nothanks@nottoday.co.uk> wrote: >On 10/09/2026 15:20, john larkin wrote: > ><xxxx>> >> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. > >If I've done the sums right, that's a capacitor bank bigger than six >beer cans storing about the same energy as one AAA cell! > >> People would notice if that were shorted. > >Yes, I used to operate capacitor banks of maybe 2-4 times that physical >size charged to 1kV and discharged via a spark gap through a marine >sparker for seismic work. Long time ago before H&S was a thing. I got one of the giant caps. It says that it's 30,000 uF but it measures 50,000. So we'll have 4000 joules with four in parallel at 200v. I think it's normal for elecs to have more initial capacitance than the nameplate value. https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg?rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-12 16:24 +1000 |
| Message-ID | <1182r72$3gl0m$1@dont-email.me> |
| In reply to | #747600 |
On 12/09/2026 7:28 am, john larkin wrote: > On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple > <nothanks@nottoday.co.uk> wrote: > >> On 10/09/2026 15:20, john larkin wrote: >> >> <xxxx>> >>> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >> >> If I've done the sums right, that's a capacitor bank bigger than six >> beer cans storing about the same energy as one AAA cell! >> >>> People would notice if that were shorted. >> >> Yes, I used to operate capacitor banks of maybe 2-4 times that physical >> size charged to 1kV and discharged via a spark gap through a marine >> sparker for seismic work. Long time ago before H&S was a thing. > > I got one of the giant caps. It says that it's 30,000 uF but it > measures 50,000. So we'll have 4000 joules with four in parallel at > 200v. > > I think it's normal for elecs to have more initial capacitance than > the nameplate value. > > https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg?rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1 One of the more depressing things about electrolytic capacitors is the need to reform them by keeping the rated voltage across them for a day or so if they have been unused for a while. The actual electrolyte is a layer of aluminium oxide on the electrode surface, and that diffuses away slowly if the capacitor is stored uncharged. In extreme cases you have apply the reforming voltage through a big resistor because the thinned down layer can no longer stand off the rated voltage. With the big resistor you can measure the reforming current as the process proceeds. Obviously the initial capacitance is higher than the rated capacitance. That may have contributed to your initial 50mF - a +50% tolerance only get you up to 45mF I reformed a couple of electroltics many years ago when I bought some military surplus electrolytics for my home built hi-fi. I didn't bother to monitor the current. -- Bill Sloman, Sydney
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| From | John R Walliker <jrwalliker@gmail.com> |
|---|---|
| Date | 2026-09-12 10:49 +0100 |
| Message-ID | <118376j$3kpl2$1@dont-email.me> |
| In reply to | #747604 |
On 12/09/2026 07:24, Bill Sloman wrote: > On 12/09/2026 7:28 am, john larkin wrote: >> On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple >> <nothanks@nottoday.co.uk> wrote: >> >>> On 10/09/2026 15:20, john larkin wrote: >>> >>> <xxxx>> >>>> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >>> >>> If I've done the sums right, that's a capacitor bank bigger than six >>> beer cans storing about the same energy as one AAA cell! >>> >>>> People would notice if that were shorted. >>> >>> Yes, I used to operate capacitor banks of maybe 2-4 times that physical >>> size charged to 1kV and discharged via a spark gap through a marine >>> sparker for seismic work. Long time ago before H&S was a thing. >> >> I got one of the giant caps. It says that it's 30,000 uF but it >> measures 50,000. So we'll have 4000 joules with four in parallel at >> 200v. >> >> I think it's normal for elecs to have more initial capacitance than >> the nameplate value. >> >> https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg? >> rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1 > > One of the more depressing things about electrolytic capacitors is the > need to reform them by keeping the rated voltage across them for a day > or so if they have been unused for a while. > > The actual electrolyte is a layer of aluminium oxide on the electrode I'm sure you didn't mean that! > surface, and that diffuses away slowly if the capacitor is stored > uncharged. In extreme cases you have apply the reforming voltage through > a big resistor because the thinned down layer can no longer stand off > the rated voltage. With the big resistor you can measure the reforming > current as the process proceeds. > > Obviously the initial capacitance is higher than the rated capacitance. > That may have contributed to your initial 50mF - a +50% tolerance only > get you up to 45mF > > I reformed a couple of electroltics many years ago when I bought some > military surplus electrolytics for my home built hi-fi. I didn't bother > to monitor the current. >
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-13 01:09 +1000 |
| Message-ID | <1183pus$3rmps$1@dont-email.me> |
| In reply to | #747608 |
On 12/09/2026 7:49 pm, John R Walliker wrote: > On 12/09/2026 07:24, Bill Sloman wrote: >> On 12/09/2026 7:28 am, john larkin wrote: >>> On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple >>> <nothanks@nottoday.co.uk> wrote: >>> >>>> On 10/09/2026 15:20, john larkin wrote: >>>> >>>> <xxxx>> >>>>> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >>>> >>>> If I've done the sums right, that's a capacitor bank bigger than six >>>> beer cans storing about the same energy as one AAA cell! >>>> >>>>> People would notice if that were shorted. >>>> >>>> Yes, I used to operate capacitor banks of maybe 2-4 times that physical >>>> size charged to 1kV and discharged via a spark gap through a marine >>>> sparker for seismic work. Long time ago before H&S was a thing. >>> >>> I got one of the giant caps. It says that it's 30,000 uF but it >>> measures 50,000. So we'll have 4000 joules with four in parallel at >>> 200v. >>> >>> I think it's normal for elecs to have more initial capacitance than >>> the nameplate value. >>> >>> https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg? >>> rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1 >> >> One of the more depressing things about electrolytic capacitors is the >> need to reform them by keeping the rated voltage across them for a day >> or so if they have been unused for a while. >> >> The actual electrolyte is a layer of aluminium oxide on the electrode > > I'm sure you didn't mean that! Correct. What I meant to type was that the "dielectric" was a layer of aluminium oxide on one electrode. >> surface, and that diffuses away slowly if the capacitor is stored >> uncharged. In extreme cases you have apply the reforming voltage >> through a big resistor because the thinned down layer can no longer >> stand off the rated voltage. With the big resistor you can measure the >> reforming current as the process proceeds. >> >> Obviously the initial capacitance is higher than the rated >> capacitance. That may have contributed to your initial 50mF - a +50% >> tolerance only get you up to 45mF >> >> I reformed a couple of electroltics many years ago when I bought some >> military surplus electrolytics for my home built hi-fi. I didn't >> bother to monitor the current. -- Bill Sloman, Sydney
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-12 07:54 -0700 |
| Message-ID | <plpaaldvjoad91tun8cpmkjrgolgr830q4@4ax.com> |
| In reply to | #747604 |
On Sat, 12 Sep 2026 16:24:19 +1000, Bill Sloman <bill.sloman@ieee.org> wrote: >On 12/09/2026 7:28 am, john larkin wrote: >> On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple >> <nothanks@nottoday.co.uk> wrote: >> >>> On 10/09/2026 15:20, john larkin wrote: >>> >>> <xxxx>> >>>> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >>> >>> If I've done the sums right, that's a capacitor bank bigger than six >>> beer cans storing about the same energy as one AAA cell! >>> >>>> People would notice if that were shorted. >>> >>> Yes, I used to operate capacitor banks of maybe 2-4 times that physical >>> size charged to 1kV and discharged via a spark gap through a marine >>> sparker for seismic work. Long time ago before H&S was a thing. >> >> I got one of the giant caps. It says that it's 30,000 uF but it >> measures 50,000. So we'll have 4000 joules with four in parallel at >> 200v. >> >> I think it's normal for elecs to have more initial capacitance than >> the nameplate value. >> >> https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg?rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1 > >One of the more depressing things about electrolytic capacitors is the >need to reform them by keeping the rated voltage across them for a day >or so if they have been unused for a while. > >The actual electrolyte is a layer of aluminium oxide on the electrode >surface, and that diffuses away slowly if the capacitor is stored >uncharged. In extreme cases you have apply the reforming voltage through >a big resistor because the thinned down layer can no longer stand off >the rated voltage. With the big resistor you can measure the reforming >current as the process proceeds. > >Obviously the initial capacitance is higher than the rated capacitance. >That may have contributed to your initial 50mF - a +50% tolerance only >get you up to 45mF > >I reformed a couple of electroltics many years ago when I bought some >military surplus electrolytics for my home built hi-fi. I didn't bother >to monitor the current. I'm thinking that they overdo the capacitance to account for later-on drying out or some electro-chemical effects, to ensure the guaranteed minimum c over the (short) specified lifetime. Caps are tricky parts. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-13 01:20 +1000 |
| Message-ID | <1183qkt$3rmps$2@dont-email.me> |
| In reply to | #747609 |
On 13/09/2026 12:54 am, john larkin wrote: > On Sat, 12 Sep 2026 16:24:19 +1000, Bill Sloman <bill.sloman@ieee.org> > wrote: > >> On 12/09/2026 7:28 am, john larkin wrote: >>> On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple >>> <nothanks@nottoday.co.uk> wrote: >>> >>>> On 10/09/2026 15:20, john larkin wrote: >>>> >>>> <xxxx>> >>>>> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >>>> >>>> If I've done the sums right, that's a capacitor bank bigger than six >>>> beer cans storing about the same energy as one AAA cell! >>>> >>>>> People would notice if that were shorted. >>>> >>>> Yes, I used to operate capacitor banks of maybe 2-4 times that physical >>>> size charged to 1kV and discharged via a spark gap through a marine >>>> sparker for seismic work. Long time ago before H&S was a thing. >>> >>> I got one of the giant caps. It says that it's 30,000 uF but it >>> measures 50,000. So we'll have 4000 joules with four in parallel at >>> 200v. >>> >>> I think it's normal for elecs to have more initial capacitance than >>> the nameplate value. >>> >>> https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg?rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1 >> >> One of the more depressing things about electrolytic capacitors is the >> need to reform them by keeping the rated voltage across them for a day >> or so if they have been unused for a while. >> >> The actual electrolyte is a layer of aluminium oxide on the electrode >> surface, and that diffuses away slowly if the capacitor is stored >> uncharged. In extreme cases you have apply the reforming voltage through >> a big resistor because the thinned down layer can no longer stand off >> the rated voltage. With the big resistor you can measure the reforming >> current as the process proceeds. >> >> Obviously the initial capacitance is higher than the rated capacitance. >> That may have contributed to your initial 50mF - a +50% tolerance only >> get you up to 45mF >> >> I reformed a couple of electroltics many years ago when I bought some >> military surplus electrolytics for my home built hi-fi. I didn't bother >> to monitor the current. > > I'm thinking that they overdo the capacitance to account for later-on > drying out or some electro-chemical effects, to ensure the guaranteed > minimum c over the (short) specified lifetime. Not that I know of. Note that the tolerance printed on your can was -10% +50%. The need to reform long unused electrolytic capacitors was well known everywhere I worked. Nobody ever warned me about any "drying out", and mythical electro-chemical effects weren't mentioned either. Back when I was a graduate student in chemistry the electrochemists did get a hard time, but back then they didn't have good tools for looking at the microscope detail of the very thin layers where the electrochemistry took place. > Caps are tricky parts. And electrolytic capacitors are even trickier than regular capacitors. Charge soak isn't nice. -- Bill Sloman, Sydney
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-12 09:12 -0700 |
| Message-ID | <19uaalh8mmvo8sqbgaovjhmeu4t2n7p8ag@4ax.com> |
| In reply to | #747615 |
On Sun, 13 Sep 2026 01:20:46 +1000, Bill Sloman <bill.sloman@ieee.org> wrote: >On 13/09/2026 12:54 am, john larkin wrote: >> On Sat, 12 Sep 2026 16:24:19 +1000, Bill Sloman <bill.sloman@ieee.org> >> wrote: >> >>> On 12/09/2026 7:28 am, john larkin wrote: >>>> On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple >>>> <nothanks@nottoday.co.uk> wrote: >>>> >>>>> On 10/09/2026 15:20, john larkin wrote: >>>>> >>>>> <xxxx>> >>>>>> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >>>>> >>>>> If I've done the sums right, that's a capacitor bank bigger than six >>>>> beer cans storing about the same energy as one AAA cell! >>>>> >>>>>> People would notice if that were shorted. >>>>> >>>>> Yes, I used to operate capacitor banks of maybe 2-4 times that physical >>>>> size charged to 1kV and discharged via a spark gap through a marine >>>>> sparker for seismic work. Long time ago before H&S was a thing. >>>> >>>> I got one of the giant caps. It says that it's 30,000 uF but it >>>> measures 50,000. So we'll have 4000 joules with four in parallel at >>>> 200v. >>>> >>>> I think it's normal for elecs to have more initial capacitance than >>>> the nameplate value. >>>> >>>> https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg?rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1 >>> >>> One of the more depressing things about electrolytic capacitors is the >>> need to reform them by keeping the rated voltage across them for a day >>> or so if they have been unused for a while. >>> >>> The actual electrolyte is a layer of aluminium oxide on the electrode >>> surface, and that diffuses away slowly if the capacitor is stored >>> uncharged. In extreme cases you have apply the reforming voltage through >>> a big resistor because the thinned down layer can no longer stand off >>> the rated voltage. With the big resistor you can measure the reforming >>> current as the process proceeds. >>> >>> Obviously the initial capacitance is higher than the rated capacitance. >>> That may have contributed to your initial 50mF - a +50% tolerance only >>> get you up to 45mF >>> >>> I reformed a couple of electroltics many years ago when I bought some >>> military surplus electrolytics for my home built hi-fi. I didn't bother >>> to monitor the current. >> >> I'm thinking that they overdo the capacitance to account for later-on >> drying out or some electro-chemical effects, to ensure the guaranteed >> minimum c over the (short) specified lifetime. > >Not that I know of. Note that the tolerance printed on your can was -10% >+50%. Hey, I saw that. It measured +66%. > >The need to reform long unused electrolytic capacitors was well known >everywhere I worked. Nobody ever warned me about any "drying out", and >mythical electro-chemical effects weren't mentioned either. Back when I >was a graduate student in chemistry the electrochemists did get a hard >time, but back then they didn't have good tools for looking at the >microscope detail of the very thin layers where the electrochemistry >took place. > >> Caps are tricky parts. > >And electrolytic capacitors are even trickier than regular capacitors. >Charge soak isn't nice. Charged to 100v and discharged for 2 seconds, that big cap went to about 0.25 volts and then only recharged itself to 2 volts. Not bad. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-13 02:53 +1000 |
| Message-ID | <1184027$3tnj6$2@dont-email.me> |
| In reply to | #747618 |
On 13/09/2026 2:12 am, john larkin wrote: > On Sun, 13 Sep 2026 01:20:46 +1000, Bill Sloman <bill.sloman@ieee.org> > wrote: > >> On 13/09/2026 12:54 am, john larkin wrote: >>> On Sat, 12 Sep 2026 16:24:19 +1000, Bill Sloman <bill.sloman@ieee.org> >>> wrote: >>> >>>> On 12/09/2026 7:28 am, john larkin wrote: >>>>> On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple >>>>> <nothanks@nottoday.co.uk> wrote: >>>>> >>>>>> On 10/09/2026 15:20, john larkin wrote: >>>>>> >>>>>> <xxxx>> >>>>>>> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >>>>>> >>>>>> If I've done the sums right, that's a capacitor bank bigger than six >>>>>> beer cans storing about the same energy as one AAA cell! >>>>>> >>>>>>> People would notice if that were shorted. >>>>>> >>>>>> Yes, I used to operate capacitor banks of maybe 2-4 times that physical >>>>>> size charged to 1kV and discharged via a spark gap through a marine >>>>>> sparker for seismic work. Long time ago before H&S was a thing. >>>>> >>>>> I got one of the giant caps. It says that it's 30,000 uF but it >>>>> measures 50,000. So we'll have 4000 joules with four in parallel at >>>>> 200v. >>>>> >>>>> I think it's normal for elecs to have more initial capacitance than >>>>> the nameplate value. >>>>> >>>>> https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg?rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1 >>>> >>>> One of the more depressing things about electrolytic capacitors is the >>>> need to reform them by keeping the rated voltage across them for a day >>>> or so if they have been unused for a while. >>>> >>>> The actual electrolyte is a layer of aluminium oxide on the electrode >>>> surface, and that diffuses away slowly if the capacitor is stored >>>> uncharged. In extreme cases you have apply the reforming voltage through >>>> a big resistor because the thinned down layer can no longer stand off >>>> the rated voltage. With the big resistor you can measure the reforming >>>> current as the process proceeds. >>>> >>>> Obviously the initial capacitance is higher than the rated capacitance. >>>> That may have contributed to your initial 50mF - a +50% tolerance only >>>> get you up to 45mF >>>> >>>> I reformed a couple of electroltics many years ago when I bought some >>>> military surplus electrolytics for my home built hi-fi. I didn't bother >>>> to monitor the current. >>> >>> I'm thinking that they overdo the capacitance to account for later-on >>> drying out or some electro-chemical effects, to ensure the guaranteed >>> minimum c over the (short) specified lifetime. >> >> Not that I know of. Note that the tolerance printed on your can was -10% >> +50%. > > Hey, I saw that. It measured +66%. Which does suggest that it had been left uncharged for long enough to need reforming. The tolerances are just arbitrary cut-offs on what's probably a Gaussian distribution. Presumably the manufacturer samples individual capacitors often enough to be confident that the distribution is stable, but don't measure every capacitor that they ship. That +66% might just have been an outlier. >> The need to reform long unused electrolytic capacitors was well known >> everywhere I worked. Nobody ever warned me about any "drying out", and >> mythical electro-chemical effects weren't mentioned either. Back when I >> was a graduate student in chemistry the electrochemists did get a hard >> time, but back then they didn't have good tools for looking at the >> microscope detail of the very thin layers where the electrochemistry >> took place. >> >>> Caps are tricky parts. >> >> And electrolytic capacitors are even trickier than regular capacitors. >> Charge soak isn't nice. > > Charged to 100v and discharged for 2 seconds, that big cap went to > about 0.25 volts and then only recharged itself to 2 volts. > > Not bad. It's more of a worry in capacitor-based A/D converters. Dual ramp and quad ramp schemes come to mind. Not all that clearly - that was back in 1979. Going from a Mylar to polycarbonate dielectric got the soak down far enough to make it tolerable. -- Bill Sloman, Sydney
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-12 12:43 -0700 |
| Message-ID | <dbabal59vi2amu0a89g76t6mo3s3ghdj54@4ax.com> |
| In reply to | #747623 |
On Sun, 13 Sep 2026 02:53:12 +1000, Bill Sloman <bill.sloman@ieee.org> wrote: >On 13/09/2026 2:12 am, john larkin wrote: >> On Sun, 13 Sep 2026 01:20:46 +1000, Bill Sloman <bill.sloman@ieee.org> >> wrote: >> >>> On 13/09/2026 12:54 am, john larkin wrote: >>>> On Sat, 12 Sep 2026 16:24:19 +1000, Bill Sloman <bill.sloman@ieee.org> >>>> wrote: >>>> >>>>> On 12/09/2026 7:28 am, john larkin wrote: >>>>>> On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple >>>>>> <nothanks@nottoday.co.uk> wrote: >>>>>> >>>>>>> On 10/09/2026 15:20, john larkin wrote: >>>>>>> >>>>>>> <xxxx>> >>>>>>>> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >>>>>>> >>>>>>> If I've done the sums right, that's a capacitor bank bigger than six >>>>>>> beer cans storing about the same energy as one AAA cell! >>>>>>> >>>>>>>> People would notice if that were shorted. >>>>>>> >>>>>>> Yes, I used to operate capacitor banks of maybe 2-4 times that physical >>>>>>> size charged to 1kV and discharged via a spark gap through a marine >>>>>>> sparker for seismic work. Long time ago before H&S was a thing. >>>>>> >>>>>> I got one of the giant caps. It says that it's 30,000 uF but it >>>>>> measures 50,000. So we'll have 4000 joules with four in parallel at >>>>>> 200v. >>>>>> >>>>>> I think it's normal for elecs to have more initial capacitance than >>>>>> the nameplate value. >>>>>> >>>>>> https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg?rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1 >>>>> >>>>> One of the more depressing things about electrolytic capacitors is the >>>>> need to reform them by keeping the rated voltage across them for a day >>>>> or so if they have been unused for a while. >>>>> >>>>> The actual electrolyte is a layer of aluminium oxide on the electrode >>>>> surface, and that diffuses away slowly if the capacitor is stored >>>>> uncharged. In extreme cases you have apply the reforming voltage through >>>>> a big resistor because the thinned down layer can no longer stand off >>>>> the rated voltage. With the big resistor you can measure the reforming >>>>> current as the process proceeds. >>>>> >>>>> Obviously the initial capacitance is higher than the rated capacitance. >>>>> That may have contributed to your initial 50mF - a +50% tolerance only >>>>> get you up to 45mF >>>>> >>>>> I reformed a couple of electroltics many years ago when I bought some >>>>> military surplus electrolytics for my home built hi-fi. I didn't bother >>>>> to monitor the current. >>>> >>>> I'm thinking that they overdo the capacitance to account for later-on >>>> drying out or some electro-chemical effects, to ensure the guaranteed >>>> minimum c over the (short) specified lifetime. >>> >>> Not that I know of. Note that the tolerance printed on your can was -10% >>> +50%. >> >> Hey, I saw that. It measured +66%. > >Which does suggest that it had been left uncharged for long enough to >need reforming. > It charged to 100 volts with a power supply that was limited to 20 mA. The rampup was very linear. >The tolerances are just arbitrary cut-offs on what's probably a Gaussian >distribution. Presumably the manufacturer samples individual capacitors >often enough to be confident that the distribution is stable, but don't >measure every capacitor that they ship. That +66% might just have been >an outlier. > >>> The need to reform long unused electrolytic capacitors was well known >>> everywhere I worked. Nobody ever warned me about any "drying out", and >>> mythical electro-chemical effects weren't mentioned either. Back when I >>> was a graduate student in chemistry the electrochemists did get a hard >>> time, but back then they didn't have good tools for looking at the >>> microscope detail of the very thin layers where the electrochemistry >>> took place. >>> >>>> Caps are tricky parts. >>> >>> And electrolytic capacitors are even trickier than regular capacitors. >>> Charge soak isn't nice. >> >> Charged to 100v and discharged for 2 seconds, that big cap went to >> about 0.25 volts and then only recharged itself to 2 volts. >> >> Not bad. > >It's more of a worry in capacitor-based A/D converters. Dual ramp and >quad ramp schemes come to mind. Not all that clearly - that was back in >1979. Going from a Mylar to polycarbonate dielectric got the soak down >far enough to make it tolerable. I remember dual-slope ADCs. I designed a few. Very long ago. IC adc's are dirt cheap now and super accurate. 24 bits for $2. The caps that people can make inside ICs are about the best caps that are possible. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-13 16:37 +1000 |
| Message-ID | <1185gap$csfm$3@dont-email.me> |
| In reply to | #747631 |
On 13/09/2026 5:43 am, john larkin wrote: > On Sun, 13 Sep 2026 02:53:12 +1000, Bill Sloman <bill.sloman@ieee.org> > wrote: > >> On 13/09/2026 2:12 am, john larkin wrote: >>> On Sun, 13 Sep 2026 01:20:46 +1000, Bill Sloman <bill.sloman@ieee.org> >>> wrote: >>> >>>> On 13/09/2026 12:54 am, john larkin wrote: >>>>> On Sat, 12 Sep 2026 16:24:19 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote: >>>>> >>>>>> On 12/09/2026 7:28 am, john larkin wrote: >>>>>>> On Fri, 11 Sep 2026 17:08:00 +0100, Simon Simple >>>>>>> <nothanks@nottoday.co.uk> wrote: >>>>>>> >>>>>>>> On 10/09/2026 15:20, john larkin wrote: >>>>>>>> >>>>>>>> <xxxx>> >>>>>>>>> 2.4 KJ is about 16 firecrackers or five .45 cal bullets worth of bang. >>>>>>>> >>>>>>>> If I've done the sums right, that's a capacitor bank bigger than six >>>>>>>> beer cans storing about the same energy as one AAA cell! >>>>>>>> >>>>>>>>> People would notice if that were shorted. >>>>>>>> >>>>>>>> Yes, I used to operate capacitor banks of maybe 2-4 times that physical >>>>>>>> size charged to 1kV and discharged via a spark gap through a marine >>>>>>>> sparker for seismic work. Long time ago before H&S was a thing. >>>>>>> >>>>>>> I got one of the giant caps. It says that it's 30,000 uF but it >>>>>>> measures 50,000. So we'll have 4000 joules with four in parallel at >>>>>>> 200v. >>>>>>> >>>>>>> I think it's normal for elecs to have more initial capacitance than >>>>>>> the nameplate value. >>>>>>> >>>>>>> https://www.dropbox.com/scl/fi/apargzu733abcq6ww7w3b/30mF_250v.jpg?rlkey=00osgeyqpxceowgqf7l32mlnr&raw=1 >>>>>> >>>>>> One of the more depressing things about electrolytic capacitors is the >>>>>> need to reform them by keeping the rated voltage across them for a day >>>>>> or so if they have been unused for a while. >>>>>> >>>>>> The actual electrolyte is a layer of aluminium oxide on the electrode >>>>>> surface, and that diffuses away slowly if the capacitor is stored >>>>>> uncharged. In extreme cases you have apply the reforming voltage through >>>>>> a big resistor because the thinned down layer can no longer stand off >>>>>> the rated voltage. With the big resistor you can measure the reforming >>>>>> current as the process proceeds. >>>>>> >>>>>> Obviously the initial capacitance is higher than the rated capacitance. >>>>>> That may have contributed to your initial 50mF - a +50% tolerance only >>>>>> get you up to 45mF >>>>>> >>>>>> I reformed a couple of electroltics many years ago when I bought some >>>>>> military surplus electrolytics for my home built hi-fi. I didn't bother >>>>>> to monitor the current. >>>>> >>>>> I'm thinking that they overdo the capacitance to account for later-on >>>>> drying out or some electro-chemical effects, to ensure the guaranteed >>>>> minimum c over the (short) specified lifetime. >>>> >>>> Not that I know of. Note that the tolerance printed on your can was -10% >>>> +50%. >>> >>> Hey, I saw that. It measured +66%. >> >> Which does suggest that it had been left uncharged for long enough to >> need reforming. >> > > It charged to 100 volts with a power supply that was limited to 20 mA. > The rampup was very linear. > > >> The tolerances are just arbitrary cut-offs on what's probably a Gaussian >> distribution. Presumably the manufacturer samples individual capacitors >> often enough to be confident that the distribution is stable, but don't >> measure every capacitor that they ship. That +66% might just have been >> an outlier. >> >>>> The need to reform long unused electrolytic capacitors was well known >>>> everywhere I worked. Nobody ever warned me about any "drying out", and >>>> mythical electro-chemical effects weren't mentioned either. Back when I >>>> was a graduate student in chemistry the electrochemists did get a hard >>>> time, but back then they didn't have good tools for looking at the >>>> microscope detail of the very thin layers where the electrochemistry >>>> took place. >>>> >>>>> Caps are tricky parts. >>>> >>>> And electrolytic capacitors are even trickier than regular capacitors. >>>> Charge soak isn't nice. >>> >>> Charged to 100v and discharged for 2 seconds, that big cap went to >>> about 0.25 volts and then only recharged itself to 2 volts. >>> >>> Not bad. >> >> It's more of a worry in capacitor-based A/D converters. Dual ramp and >> quad ramp schemes come to mind. Not all that clearly - that was back in >> 1979. Going from a Mylar to polycarbonate dielectric got the soak down >> far enough to make it tolerable. > > I remember dual-slope ADCs. I designed a few. Very long ago. IC adc's > are dirt cheap now and super accurate. 24 bits for $2. Sigma delta parts. Back when I last used one, in 1993, it spat out 24-bits - three bytes - but the accuracy spec was 20-bit. There were more precise versions around but they weren't dirt cheap. Sloman A.W., Buggs P., Molloy J., and Stewart D. “A microcontroller-based driver to stabilise the temperature of an optical stage to 1mK in the range 4C to 38C, using a Peltier heat pump and a thermistor sensor” Measurement Science and Technology, 7 1653-64 (1996) > The caps that people can make inside ICs are about the best caps that > are possible. If a little too small for you application. -- Bill Sloman. Sydney
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