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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 | 19 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
Page 13 of 13 — ← Prev page 1 … 11 12 [13]
| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-29 17:22 +1000 |
| Message-ID | <119fovp$31pu8$3@dont-email.me> |
| In reply to | #748307 |
On 29/09/2026 3:15 am, john larkin wrote: > On Mon, 28 Sep 2026 12:35:14 +1000, Bill Sloman <bill.sloman@ieee.org> > wrote: > >> On 28/09/2026 12:59 am, john larkin wrote: >>> On Sun, 27 Sep 2026 20:55:57 +1000, Bill Sloman <bill.sloman@ieee.org> >>> wrote: >>> >>>> On 27/09/2026 8:20 pm, john larkin wrote: >>>>> On Sun, 27 Sep 2026 16:22:30 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote: >>>>> >>>>>> On 27/09/2026 2:24 am, john larkin wrote: >>>>>>> On Sat, 26 Sep 2026 15:56:29 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>>> wrote: >>>>>>> >>>>>>>> On 26/09/2026 3:59 am, Jeroen Belleman wrote: >>>>>>>>> On 9/25/26 16:38, john larkin wrote: >>>>>>>>>> On Fri, 25 Sep 2026 12:28:01 +0200, Jeroen Belleman >>>>>>>>>> <jeroen@nospam.please> wrote: >>>>>>>>>> >>>>>>>>>>> On 9/25/26 11:59, John R Walliker wrote: >>>>>>>>>>>> On 25/09/2026 08:38, Jeroen Belleman wrote: >>>>>>>>>>>>> On 9/25/26 09:09, Bill Sloman wrote: >>>>>>>>>>>>>> On 25/09/2026 4:55 am, john larkin wrote: >>>>>>>>>>>>>>> On Thu, 24 Sep 2026 07:54:55 -0400, legg <legg@nospam.magma.ca> >>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Wed, 23 Sep 2026 21:42:35 +0100, >>>>>>>>>>>>>>>> liz@poppyrecords.invalid.invalid >>>>>>>>>>>>>>>> (Liz Tuddenham) wrote: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> 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. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> I had some relevant experience yesterday: >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> I was working on a radio transmitter with a 750 H.T. rail and had >>>>>>>>>>>>>>>>> switched it off to make some changes to the circuit. As I leaned >>>>>>>>>>>>>>>>> forward with my hand on the chassis, the palm of that hand touched >>>>>>>>>>>>>>>>> the >>>>>>>>>>>>>>>>> H.T. tag on a tagstrip and I received a painful elecric shock and >>>>>>>>>>>>>>>>> some >>>>>>>>>>>>>>>>> superficial burns. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> It appears the discharge resistors in the power supply had gone >>>>>>>>>>>>>>>>> high >>>>>>>>>>>>>>>>> resistance and were taking a couple of minutes to pull the 750v >>>>>>>>>>>>>>>>> rail >>>>>>>>>>>>>>>>> down to 100v. Given the time interval between switching off and >>>>>>>>>>>>>>>>> getting >>>>>>>>>>>>>>>>> the shock, I estimate it must still have been around 700v from a >>>>>>>>>>>>>>>>> couple >>>>>>>>>>>>>>>>> of 100uf capacitors in series. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> I don't have any suitable discharge resistors in stock and I and >>>>>>>>>>>>>>>>> have no >>>>>>>>>>>>>>>>> intention of doing their job for them a second time, so I have >>>>>>>>>>>>>>>>> glued a >>>>>>>>>>>>>>>>> strip of plastic along the top of the tagstrip as a temporary >>>>>>>>>>>>>>>>> measure. >>>>>>>>>>>>>>>>> I will order some replacement resistors ASAP and am happy to >>>>>>>>>>>>>>>>> report that >>>>>>>>>>>>>>>>> the burn marks have almost disappeared >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Were you working alone? >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Just about the only workplace fatality I'm close to was >>>>>>>>>>>>>>>> a tech at Varian. Alone in the plant, he bypassed safety >>>>>>>>>>>>>>>> interlocks on a TWT supply test cage to speed up his job. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Varian was our biggest customer for many years, the NMR division. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Other technologies displaced NMR. The superconductive magnets >>>>>>>>>>>>>>> were too >>>>>>>>>>>>>>> expensive. Agilent bought Varian and killed the NMR operation. >>>>>>>>>>>>>> >>>>>>>>>>>>>> The local hospitals are still full of Magnetic Resonance Scanners. >>>>>>>>>>>>>> The Nuclear tag worried patients so it got dropped from the name. >>>>>>>>>>>>>> >>>>>>>>>>>>>> If Varian lost money on the operation, they were probably doing >>>>>>>>>>>>>> something wrong. Super-conducting magnets are expensive, but other >>>>>>>>>>>>>> manufacturers still seem to be making money by building and selling >>>>>>>>>>>>>> the technology. >>>>>>>>>>>>>> >>>>>>>>>>>>>> <snip> >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> What technologies _displaced_ NMR? >>>>>>>>>> >>>>>>>>>> Ask Professor Google. >>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> Jeroen Belleman >>>>>>>>>>>> >>>>>>>>>>>> Nothing has. >>>>>>>>>>>> MRI scans are still the preferred technology for many investigations. >>>>>>>>>>> >>>>>>>>>>> That's indeed what I believed. >>>>>>>>>>> >>>>>>>>>>>> There are some interesting enhancements such as the use of >>>>>>>>>>>> hyperpolarised Xenon for lung imaging and function analysis. >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> I see. Atoms with an odd number of protons and/or neutrons can >>>>>>>>>>> resonate in a magnetic field and there are lots of applications >>>>>>>>>>> of nuclear magnetic resonance other than medical imaging. >>>>>>>>>>> >>>>>>>>>>> Jeroen Belleman >>>>>>>>>> >>>>>>>>>> The Varian NMR group did a little micro-imaging (we furnished the >>>>>>>>>> gradient drivers and temperature controllers) but most of the business >>>>>>>>>> was analytical chemistry, not imaging. >>>>>>>>>> >>>>>>>>>> I think Bruker still does some analytical NMR. >>>>>>>>>> >>>>>>>>>> Varian should have owned the medical imaging buisiness but blew that. >>>>>>>>>> >>>>>>>>>> Kids often do NMR as a science project. The hydrogen line in water is >>>>>>>>>> huge. >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> John Larkin >>>>>>>>>> Highland Tech Glen Canyon Design Center >>>>>>>>>> Lunatic Fringe Electronics >>>>>>>>> >>>>>>>>> >>>>>>>>> I'm pretty convinced NMR is alive and well. I wanted to hear >>>>>>>>> from you what other technologies replaced it. >>>>>>>> >>>>>>>> As a sort of proof of intellectual life? John Larkin thinks that Donald >>>>>>>> Trump has "common sense". He's not exactly an intellectual power-house. >>>>>>> >>>>>>> You must think and dream Trump all the time. >>>>>> >>>>>> Far from it. But his particular brand of ineptitude does resonate with >>>>>> yours. The local press does remind me about him from time to time - he >>>>>> does screw up remarkably frequently - but the US does have a lot of >>>>>> political clowns, and always has had. Weapons of mass destruction do >>>>>> come to mind. >>>>>> >>>>>>> Sad. >>>>>> >>>>>> It certainly would be, if it were true. Like most of your insulting >>>>>> speculations, it reflects your bizarre preoccupations, not mine. >>>>> >>>>> I dare you to go a month without mentioning Trump. >>>>> >>>>> Second dare, a month without insulting anyone. Or even a week. >>>> >>>> You may fancy yourself a a political censor. Nobody sane is going to >>>> take you seriously in that role. >>> >>> Do you? >> >> Obviously not. >> >>>> Your idea of what constitutes an insult is pretty strange too. I'm not >>>> going to waste my time thinking about whether you would approve of what >>>> I might be thinking about posting. >>>> >>>>> Most of my non-winter preoccupations involve electronics. Yes, many >>>>> are bizarre. >>>> >>>> Probably quite a few more of them than you realise. >>> >>> crazy ideas. >> >> Not often. > > True. Not many engineers are willing to allow crazy ideas into their > heads. And not many engineers invent things. I've known several. They didn't go in for crazy ideas. Sometimes they'd have to put in some work to get other people to understand what they were proposing. >>> The path to good ideas is often through ideas that other people think are crazy. >> >> Even rarer. Some people do get attached to their silly ideas, and tout >> them as if they were good ideas. Donald Trump and tariffs do come to >> mind, despite your enthusiasm for censoring my thought processes. > > Yikes. Everything is Trump to you. A crazy idea, and not remotely productive. Trump is a widely advertised horrible example of a lot of intellectual errors, and gets cited as prominent example for a lot of mistakes. Get used to it. The mid-terms may put him back in his box, but sadly he's unlikely to get thrown out of office, or out of his bully pulpit for broadcasting his lunatic delusions. -- Bill Sloman, Sydney
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-26 07:20 -0700 |
| Message-ID | <1jkfblhvq884l2gb8d43hfas3ru0cuk0td@4ax.com> |
| In reply to | #748202 |
On Fri, 25 Sep 2026 19:59:43 +0200, Jeroen Belleman <jeroen@nospam.please> wrote: >On 9/25/26 16:38, john larkin wrote: >> On Fri, 25 Sep 2026 12:28:01 +0200, Jeroen Belleman >> <jeroen@nospam.please> wrote: >> >>> On 9/25/26 11:59, John R Walliker wrote: >>>> On 25/09/2026 08:38, Jeroen Belleman wrote: >>>>> On 9/25/26 09:09, Bill Sloman wrote: >>>>>> On 25/09/2026 4:55 am, john larkin wrote: >>>>>>> On Thu, 24 Sep 2026 07:54:55 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>> >>>>>>>> On Wed, 23 Sep 2026 21:42:35 +0100, liz@poppyrecords.invalid.invalid >>>>>>>> (Liz Tuddenham) wrote: >>>>>>>> >>>>>>>>> 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. >>>>>>>>> >>>>>>>>> I had some relevant experience yesterday: >>>>>>>>> >>>>>>>>> I was working on a radio transmitter with a 750 H.T. rail and had >>>>>>>>> switched it off to make some changes to the circuit. As I leaned >>>>>>>>> forward with my hand on the chassis, the palm of that hand touched >>>>>>>>> the >>>>>>>>> H.T. tag on a tagstrip and I received a painful elecric shock and >>>>>>>>> some >>>>>>>>> superficial burns. >>>>>>>>> >>>>>>>>> It appears the discharge resistors in the power supply had gone high >>>>>>>>> resistance and were taking a couple of minutes to pull the 750v rail >>>>>>>>> down to 100v. Given the time interval between switching off and >>>>>>>>> getting >>>>>>>>> the shock, I estimate it must still have been around 700v from a >>>>>>>>> couple >>>>>>>>> of 100uf capacitors in series. >>>>>>>>> >>>>>>>>> I don't have any suitable discharge resistors in stock and I and >>>>>>>>> have no >>>>>>>>> intention of doing their job for them a second time, so I have >>>>>>>>> glued a >>>>>>>>> strip of plastic along the top of the tagstrip as a temporary >>>>>>>>> measure. >>>>>>>>> I will order some replacement resistors ASAP and am happy to >>>>>>>>> report that >>>>>>>>> the burn marks have almost disappeared >>>>>>>> >>>>>>>> Were you working alone? >>>>>>>> >>>>>>>> Just about the only workplace fatality I'm close to was >>>>>>>> a tech at Varian. Alone in the plant, he bypassed safety >>>>>>>> interlocks on a TWT supply test cage to speed up his job. >>>>>>> >>>>>>> >>>>>>> Varian was our biggest customer for many years, the NMR division. >>>>>>> >>>>>>> Other technologies displaced NMR. The superconductive magnets were too >>>>>>> expensive. Agilent bought Varian and killed the NMR operation. >>>>>> >>>>>> The local hospitals are still full of Magnetic Resonance Scanners. >>>>>> The Nuclear tag worried patients so it got dropped from the name. >>>>>> >>>>>> If Varian lost money on the operation, they were probably doing >>>>>> something wrong. Super-conducting magnets are expensive, but other >>>>>> manufacturers still seem to be making money by building and selling >>>>>> the technology. >>>>>> >>>>>> <snip> >>>>>> >>>>> >>>>> What technologies _displaced_ NMR? >> >> Ask Professor Google. >> >>>>> >>>>> Jeroen Belleman >>>> >>>> Nothing has. >>>> MRI scans are still the preferred technology for many investigations. >>> >>> That's indeed what I believed. >>> >>>> There are some interesting enhancements such as the use of >>>> hyperpolarised Xenon for lung imaging and function analysis. >>>> >>> >>> I see. Atoms with an odd number of protons and/or neutrons can >>> resonate in a magnetic field and there are lots of applications >>> of nuclear magnetic resonance other than medical imaging. >>> >>> Jeroen Belleman >> >> The Varian NMR group did a little micro-imaging (we furnished the >> gradient drivers and temperature controllers) but most of the business >> was analytical chemistry, not imaging. >> >> I think Bruker still does some analytical NMR. >> >> Varian should have owned the medical imaging buisiness but blew that. >> >> Kids often do NMR as a science project. The hydrogen line in water is >> huge. >> >> >> John Larkin >> Highland Tech Glen Canyon Design Center >> Lunatic Fringe Electronics > > >I'm pretty convinced NMR is alive and well. I wanted to hear >from you what other technologies replaced it. > >Jeroen Belleman One thing is tagging molecules with flourescent add-ons and counting single photons, on a surface or flowing though a capillary. I've seen labs with a giant warm superconductive magnet in the corner collecting dust, because the budget couldn't afford liquid helium. The big medical imagers are starting to include reliquifiers. "Liquid nitrogen costs as much as beer and liquid helium costs as much as whiskey." I spilled a lot of LN2 on the floor once and froze my knee. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-27 01:26 +1000 |
| Message-ID | <1198o7d$ibsa$2@dont-email.me> |
| In reply to | #748233 |
On 27/09/2026 12:20 am, john larkin wrote: > On Fri, 25 Sep 2026 19:59:43 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 9/25/26 16:38, john larkin wrote: >>> On Fri, 25 Sep 2026 12:28:01 +0200, Jeroen Belleman >>> <jeroen@nospam.please> wrote: >>> >>>> On 9/25/26 11:59, John R Walliker wrote: >>>>> On 25/09/2026 08:38, Jeroen Belleman wrote: >>>>>> On 9/25/26 09:09, Bill Sloman wrote: >>>>>>> On 25/09/2026 4:55 am, john larkin wrote: >>>>>>>> On Thu, 24 Sep 2026 07:54:55 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>> >>>>>>>>> On Wed, 23 Sep 2026 21:42:35 +0100, liz@poppyrecords.invalid.invalid >>>>>>>>> (Liz Tuddenham) wrote: >>>>>>>>> >>>>>>>>>> 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. >>>>>>>>>> >>>>>>>>>> I had some relevant experience yesterday: >>>>>>>>>> >>>>>>>>>> I was working on a radio transmitter with a 750 H.T. rail and had >>>>>>>>>> switched it off to make some changes to the circuit. As I leaned >>>>>>>>>> forward with my hand on the chassis, the palm of that hand touched >>>>>>>>>> the >>>>>>>>>> H.T. tag on a tagstrip and I received a painful elecric shock and >>>>>>>>>> some >>>>>>>>>> superficial burns. >>>>>>>>>> >>>>>>>>>> It appears the discharge resistors in the power supply had gone high >>>>>>>>>> resistance and were taking a couple of minutes to pull the 750v rail >>>>>>>>>> down to 100v. Given the time interval between switching off and >>>>>>>>>> getting >>>>>>>>>> the shock, I estimate it must still have been around 700v from a >>>>>>>>>> couple >>>>>>>>>> of 100uf capacitors in series. >>>>>>>>>> >>>>>>>>>> I don't have any suitable discharge resistors in stock and I and >>>>>>>>>> have no >>>>>>>>>> intention of doing their job for them a second time, so I have >>>>>>>>>> glued a >>>>>>>>>> strip of plastic along the top of the tagstrip as a temporary >>>>>>>>>> measure. >>>>>>>>>> I will order some replacement resistors ASAP and am happy to >>>>>>>>>> report that >>>>>>>>>> the burn marks have almost disappeared >>>>>>>>> >>>>>>>>> Were you working alone? >>>>>>>>> >>>>>>>>> Just about the only workplace fatality I'm close to was >>>>>>>>> a tech at Varian. Alone in the plant, he bypassed safety >>>>>>>>> interlocks on a TWT supply test cage to speed up his job. >>>>>>>> >>>>>>>> >>>>>>>> Varian was our biggest customer for many years, the NMR division. >>>>>>>> >>>>>>>> Other technologies displaced NMR. The superconductive magnets were too >>>>>>>> expensive. Agilent bought Varian and killed the NMR operation. >>>>>>> >>>>>>> The local hospitals are still full of Magnetic Resonance Scanners. >>>>>>> The Nuclear tag worried patients so it got dropped from the name. >>>>>>> >>>>>>> If Varian lost money on the operation, they were probably doing >>>>>>> something wrong. Super-conducting magnets are expensive, but other >>>>>>> manufacturers still seem to be making money by building and selling >>>>>>> the technology. >>>>>>> >>>>>>> <snip> >>>>>>> >>>>>> >>>>>> What technologies _displaced_ NMR? >>> >>> Ask Professor Google. >>> >>>>>> >>>>>> Jeroen Belleman >>>>> >>>>> Nothing has. >>>>> MRI scans are still the preferred technology for many investigations. >>>> >>>> That's indeed what I believed. >>>> >>>>> There are some interesting enhancements such as the use of >>>>> hyperpolarised Xenon for lung imaging and function analysis. >>>>> >>>> >>>> I see. Atoms with an odd number of protons and/or neutrons can >>>> resonate in a magnetic field and there are lots of applications >>>> of nuclear magnetic resonance other than medical imaging. >>>> >>>> Jeroen Belleman >>> >>> The Varian NMR group did a little micro-imaging (we furnished the >>> gradient drivers and temperature controllers) but most of the business >>> was analytical chemistry, not imaging. >>> >>> I think Bruker still does some analytical NMR. >>> >>> Varian should have owned the medical imaging buisiness but blew that. >>> >>> Kids often do NMR as a science project. The hydrogen line in water is >>> huge. >>> >>> >>> John Larkin >>> Highland Tech Glen Canyon Design Center >>> Lunatic Fringe Electronics >> >> >> I'm pretty convinced NMR is alive and well. I wanted to hear >>from you what other technologies replaced it. > > One thing is tagging molecules with fluorescent add-ons and counting > single photons, on a surface or flowing though a capillary. It's not exactly an imaging technique. Single photon counting is slow. > I've seen labs with a giant warm superconductive magnet in the corner > collecting dust, because the budget couldn't afford liquid helium. > > The big medical imagers are starting to include reliquifiers. Anybody sensible recirculates their helium. > "Liquid nitrogen costs as much as beer and liquid helium costs as much > as whiskey." But the atmosphere is full of nitrogen. Terrestrial helium is emitted as alpha particle by radioactive elements and can accumulate in in natural gas deposits (up to 7% by volume). There isn't all that much of it and you don't want to throw it away. As a graduate student I kept the gas traps on my vacuum line cold with daily doses of liquid nitrogen > I spilled a lot of LN2 on the floor once and froze my knee. Nobody in the Melbourne University Chemistry Department was that clumsy. There was some spillage, but no frostbite that I knew of. -- Bill Sloman, Sydney
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| From | Jeroen Belleman <jeroen@nospam.please> |
|---|---|
| Date | 2026-09-26 22:58 +0200 |
| Message-ID | <1199bm2$psc7$2@dont-email.me> |
| In reply to | #748233 |
On 9/26/26 16:20, john larkin wrote: > On Fri, 25 Sep 2026 19:59:43 +0200, Jeroen Belleman > <jeroen@nospam.please> wrote: > >> On 9/25/26 16:38, john larkin wrote: >>> On Fri, 25 Sep 2026 12:28:01 +0200, Jeroen Belleman >>> <jeroen@nospam.please> wrote: >>> >>>> On 9/25/26 11:59, John R Walliker wrote: >>>>> On 25/09/2026 08:38, Jeroen Belleman wrote: >>>>>> On 9/25/26 09:09, Bill Sloman wrote: >>>>>>> On 25/09/2026 4:55 am, john larkin wrote: >>>>>>>> On Thu, 24 Sep 2026 07:54:55 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>> >>>>>>>>> On Wed, 23 Sep 2026 21:42:35 +0100, liz@poppyrecords.invalid.invalid >>>>>>>>> (Liz Tuddenham) wrote: >>>>>>>>> >>>>>>>>>> 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. >>>>>>>>>> >>>>>>>>>> I had some relevant experience yesterday: >>>>>>>>>> >>>>>>>>>> I was working on a radio transmitter with a 750 H.T. rail and had >>>>>>>>>> switched it off to make some changes to the circuit. As I leaned >>>>>>>>>> forward with my hand on the chassis, the palm of that hand touched >>>>>>>>>> the >>>>>>>>>> H.T. tag on a tagstrip and I received a painful elecric shock and >>>>>>>>>> some >>>>>>>>>> superficial burns. >>>>>>>>>> >>>>>>>>>> It appears the discharge resistors in the power supply had gone high >>>>>>>>>> resistance and were taking a couple of minutes to pull the 750v rail >>>>>>>>>> down to 100v. Given the time interval between switching off and >>>>>>>>>> getting >>>>>>>>>> the shock, I estimate it must still have been around 700v from a >>>>>>>>>> couple >>>>>>>>>> of 100uf capacitors in series. >>>>>>>>>> >>>>>>>>>> I don't have any suitable discharge resistors in stock and I and >>>>>>>>>> have no >>>>>>>>>> intention of doing their job for them a second time, so I have >>>>>>>>>> glued a >>>>>>>>>> strip of plastic along the top of the tagstrip as a temporary >>>>>>>>>> measure. >>>>>>>>>> I will order some replacement resistors ASAP and am happy to >>>>>>>>>> report that >>>>>>>>>> the burn marks have almost disappeared >>>>>>>>> >>>>>>>>> Were you working alone? >>>>>>>>> >>>>>>>>> Just about the only workplace fatality I'm close to was >>>>>>>>> a tech at Varian. Alone in the plant, he bypassed safety >>>>>>>>> interlocks on a TWT supply test cage to speed up his job. >>>>>>>> >>>>>>>> >>>>>>>> Varian was our biggest customer for many years, the NMR division. >>>>>>>> >>>>>>>> Other technologies displaced NMR. The superconductive magnets were too >>>>>>>> expensive. Agilent bought Varian and killed the NMR operation. >>>>>>> >>>>>>> The local hospitals are still full of Magnetic Resonance Scanners. >>>>>>> The Nuclear tag worried patients so it got dropped from the name. >>>>>>> >>>>>>> If Varian lost money on the operation, they were probably doing >>>>>>> something wrong. Super-conducting magnets are expensive, but other >>>>>>> manufacturers still seem to be making money by building and selling >>>>>>> the technology. >>>>>>> >>>>>>> <snip> >>>>>>> >>>>>> >>>>>> What technologies _displaced_ NMR? >>> >>> Ask Professor Google. >>> >>>>>> >>>>>> Jeroen Belleman >>>>> >>>>> Nothing has. >>>>> MRI scans are still the preferred technology for many investigations. >>>> >>>> That's indeed what I believed. >>>> >>>>> There are some interesting enhancements such as the use of >>>>> hyperpolarised Xenon for lung imaging and function analysis. >>>>> >>>> >>>> I see. Atoms with an odd number of protons and/or neutrons can >>>> resonate in a magnetic field and there are lots of applications >>>> of nuclear magnetic resonance other than medical imaging. >>>> >>>> Jeroen Belleman >>> >>> The Varian NMR group did a little micro-imaging (we furnished the >>> gradient drivers and temperature controllers) but most of the business >>> was analytical chemistry, not imaging. >>> >>> I think Bruker still does some analytical NMR. >>> >>> Varian should have owned the medical imaging buisiness but blew that. >>> >>> Kids often do NMR as a science project. The hydrogen line in water is >>> huge. >>> >>> >>> John Larkin >>> Highland Tech Glen Canyon Design Center >>> Lunatic Fringe Electronics >> >> >> I'm pretty convinced NMR is alive and well. I wanted to hear >>from you what other technologies replaced it. >> >> Jeroen Belleman > > One thing is tagging molecules with flourescent add-ons and counting > single photons, on a surface or flowing though a capillary. > > I've seen labs with a giant warm superconductive magnet in the corner > collecting dust, because the budget couldn't afford liquid helium. > > The big medical imagers are starting to include reliquifiers. > > "Liquid nitrogen costs as much as beer and liquid helium costs as much > as whiskey." > > I spilled a lot of LN2 on the floor once and froze my knee. > > > John Larkin > Highland Tech Glen Canyon Design Center > Lunatic Fringe Electronics Medical MRI is such a beautiful invention. If there was something better, I'd expect to have heard of it. Regarding the price of LHe, during the long shutdown of the LHC in 2019-2020, CERN *sold* its helium, and then bought it back when the LHC was about to be restarted! The LHC cryo system contains about 100 tons of LHe. I have no knowledge of the financial consequences of those transactions. I don't know what they'll do this time around. The LHC was stopped in June and will undergo upgrades and repairs for three years to come. Jeroen Belleman
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-26 16:20 -0700 |
| Message-ID | <dokgbld3dc9p4dqm8o1vp6325rnvdjvmim@4ax.com> |
| In reply to | #748253 |
On Sat, 26 Sep 2026 22:58:42 +0200, Jeroen Belleman <jeroen@nospam.please> wrote: >On 9/26/26 16:20, john larkin wrote: >> On Fri, 25 Sep 2026 19:59:43 +0200, Jeroen Belleman >> <jeroen@nospam.please> wrote: >> >>> On 9/25/26 16:38, john larkin wrote: >>>> On Fri, 25 Sep 2026 12:28:01 +0200, Jeroen Belleman >>>> <jeroen@nospam.please> wrote: >>>> >>>>> On 9/25/26 11:59, John R Walliker wrote: >>>>>> On 25/09/2026 08:38, Jeroen Belleman wrote: >>>>>>> On 9/25/26 09:09, Bill Sloman wrote: >>>>>>>> On 25/09/2026 4:55 am, john larkin wrote: >>>>>>>>> On Thu, 24 Sep 2026 07:54:55 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>>>>> >>>>>>>>>> On Wed, 23 Sep 2026 21:42:35 +0100, liz@poppyrecords.invalid.invalid >>>>>>>>>> (Liz Tuddenham) wrote: >>>>>>>>>> >>>>>>>>>>> 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. >>>>>>>>>>> >>>>>>>>>>> I had some relevant experience yesterday: >>>>>>>>>>> >>>>>>>>>>> I was working on a radio transmitter with a 750 H.T. rail and had >>>>>>>>>>> switched it off to make some changes to the circuit. As I leaned >>>>>>>>>>> forward with my hand on the chassis, the palm of that hand touched >>>>>>>>>>> the >>>>>>>>>>> H.T. tag on a tagstrip and I received a painful elecric shock and >>>>>>>>>>> some >>>>>>>>>>> superficial burns. >>>>>>>>>>> >>>>>>>>>>> It appears the discharge resistors in the power supply had gone high >>>>>>>>>>> resistance and were taking a couple of minutes to pull the 750v rail >>>>>>>>>>> down to 100v. Given the time interval between switching off and >>>>>>>>>>> getting >>>>>>>>>>> the shock, I estimate it must still have been around 700v from a >>>>>>>>>>> couple >>>>>>>>>>> of 100uf capacitors in series. >>>>>>>>>>> >>>>>>>>>>> I don't have any suitable discharge resistors in stock and I and >>>>>>>>>>> have no >>>>>>>>>>> intention of doing their job for them a second time, so I have >>>>>>>>>>> glued a >>>>>>>>>>> strip of plastic along the top of the tagstrip as a temporary >>>>>>>>>>> measure. >>>>>>>>>>> I will order some replacement resistors ASAP and am happy to >>>>>>>>>>> report that >>>>>>>>>>> the burn marks have almost disappeared >>>>>>>>>> >>>>>>>>>> Were you working alone? >>>>>>>>>> >>>>>>>>>> Just about the only workplace fatality I'm close to was >>>>>>>>>> a tech at Varian. Alone in the plant, he bypassed safety >>>>>>>>>> interlocks on a TWT supply test cage to speed up his job. >>>>>>>>> >>>>>>>>> >>>>>>>>> Varian was our biggest customer for many years, the NMR division. >>>>>>>>> >>>>>>>>> Other technologies displaced NMR. The superconductive magnets were too >>>>>>>>> expensive. Agilent bought Varian and killed the NMR operation. >>>>>>>> >>>>>>>> The local hospitals are still full of Magnetic Resonance Scanners. >>>>>>>> The Nuclear tag worried patients so it got dropped from the name. >>>>>>>> >>>>>>>> If Varian lost money on the operation, they were probably doing >>>>>>>> something wrong. Super-conducting magnets are expensive, but other >>>>>>>> manufacturers still seem to be making money by building and selling >>>>>>>> the technology. >>>>>>>> >>>>>>>> <snip> >>>>>>>> >>>>>>> >>>>>>> What technologies _displaced_ NMR? >>>> >>>> Ask Professor Google. >>>> >>>>>>> >>>>>>> Jeroen Belleman >>>>>> >>>>>> Nothing has. >>>>>> MRI scans are still the preferred technology for many investigations. >>>>> >>>>> That's indeed what I believed. >>>>> >>>>>> There are some interesting enhancements such as the use of >>>>>> hyperpolarised Xenon for lung imaging and function analysis. >>>>>> >>>>> >>>>> I see. Atoms with an odd number of protons and/or neutrons can >>>>> resonate in a magnetic field and there are lots of applications >>>>> of nuclear magnetic resonance other than medical imaging. >>>>> >>>>> Jeroen Belleman >>>> >>>> The Varian NMR group did a little micro-imaging (we furnished the >>>> gradient drivers and temperature controllers) but most of the business >>>> was analytical chemistry, not imaging. >>>> >>>> I think Bruker still does some analytical NMR. >>>> >>>> Varian should have owned the medical imaging buisiness but blew that. >>>> >>>> Kids often do NMR as a science project. The hydrogen line in water is >>>> huge. >>>> >>>> >>>> John Larkin >>>> Highland Tech Glen Canyon Design Center >>>> Lunatic Fringe Electronics >>> >>> >>> I'm pretty convinced NMR is alive and well. I wanted to hear >>>from you what other technologies replaced it. >>> >>> Jeroen Belleman >> >> One thing is tagging molecules with flourescent add-ons and counting >> single photons, on a surface or flowing though a capillary. >> >> I've seen labs with a giant warm superconductive magnet in the corner >> collecting dust, because the budget couldn't afford liquid helium. >> >> The big medical imagers are starting to include reliquifiers. >> >> "Liquid nitrogen costs as much as beer and liquid helium costs as much >> as whiskey." >> >> I spilled a lot of LN2 on the floor once and froze my knee. >> >> >> John Larkin >> Highland Tech Glen Canyon Design Center >> Lunatic Fringe Electronics > >Medical MRI is such a beautiful invention. If there was >something better, I'd expect to have heard of it. https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Jan Panteltje <alien@comet.invalid> |
|---|---|
| Date | 2026-09-27 07:39 +0000 |
| Message-ID | <119ah7q$150r1$1@dont-email.me> |
| In reply to | #748256 |
>john larkin <jl@glen--canyon.com>wrote: > >https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 Is that you?
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-27 03:29 -0700 |
| Message-ID | <mgrhbllqjj1ibrmg546d6j10a7h2n54uru@4ax.com> |
| In reply to | #748262 |
On Sun, 27 Sep 2026 07:39:37 GMT, Jan Panteltje <alien@comet.invalid> wrote: >>john larkin <jl@glen--canyon.com>wrote: >> >>https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 > >Is that you? Yes. I had a head injury and volunteered for a study and got MRI'd about once a month for most of a year. It was kind of boring. I got cat scanned three times within about an hour of my crash. That only takes a minute or so. Our local trauma center at SF General Hospital is great. I think Mark Zuckerberg bought it for his wife. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Jan Panteltje <alien@comet.invalid> |
|---|---|
| Date | 2026-09-27 13:50 +0000 |
| Message-ID | <119b6ua$1cffc$1@dont-email.me> |
| In reply to | #748269 |
>john larkin <jl@glen--canyon.com>wrote: >>On Sun, 27 Sep 2026 07:39:37 GMT, Jan Panteltje <alien@comet.invalid> >wrote: > >>>john larkin <jl@glen--canyon.com>wrote: >>> >>>https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 >> >>Is that you? > >Yes. I had a head injury and volunteered for a study and got MRI'd >about once a month for most of a year. It was kind of boring. > >I got cat scanned three times within about an hour of my crash. That >only takes a minute or so. > >Our local trauma center at SF General Hospital is great. I think Mark >Zuckerberg bought it for his wife. I once worked via an agency several month in a university hospital here one of the things I was tasked with was keeping that stuff running. We had all sorts of stuff, mass spectrometers and super conducting stuff too. Interesting DNA stuff, all sorts of stuff the students came up with and that needed electronics too.
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-27 08:04 -0700 |
| Message-ID | <tsbibld18e17q6kdggp3gdt13tvcan9j5d@4ax.com> |
| In reply to | #748272 |
On Sun, 27 Sep 2026 13:50:01 GMT, Jan Panteltje <alien@comet.invalid> wrote: >>john larkin <jl@glen--canyon.com>wrote: >>>On Sun, 27 Sep 2026 07:39:37 GMT, Jan Panteltje <alien@comet.invalid> >>wrote: >> >>>>john larkin <jl@glen--canyon.com>wrote: >>>> >>>>https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 >>> >>>Is that you? >> >>Yes. I had a head injury and volunteered for a study and got MRI'd >>about once a month for most of a year. It was kind of boring. >> >>I got cat scanned three times within about an hour of my crash. That >>only takes a minute or so. >> >>Our local trauma center at SF General Hospital is great. I think Mark >>Zuckerberg bought it for his wife. > >I once worked via an agency several month in a university hospital here >one of the things I was tasked with was keeping that stuff running. >We had all sorts of stuff, mass spectrometers and super conducting stuff too. >Interesting DNA stuff, all sorts of stuff the students came up with and >that needed electronics too. Universities often have an electronics shop. It ususlly doesn't get a lot of respect but does get a lot of interesting problems. The Art Of Electronics came out of such a shop. In high school, I worked summers at the physics-electronics shop at LSUNO. It was a great experience. John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Jan Panteltje <alien@comet.invalid> |
|---|---|
| Date | 2026-09-27 15:16 +0000 |
| Message-ID | <119bc1a$1ed9s$1@dont-email.me> |
| In reply to | #748276 |
>john larkin <jl@glen--canyon.com>wrote: >>On Sun, 27 Sep 2026 13:50:01 GMT, Jan Panteltje <alien@comet.invalid> >wrote: > >>>john larkin <jl@glen--canyon.com>wrote: >>>>On Sun, 27 Sep 2026 07:39:37 GMT, Jan Panteltje <alien@comet.invalid> >>>wrote: >>> >>>>>john larkin <jl@glen--canyon.com>wrote: >>>>> >>>>>https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 >>>> >>>>Is that you? >>> >>>Yes. I had a head injury and volunteered for a study and got MRI'd >>>about once a month for most of a year. It was kind of boring. >>> >>>I got cat scanned three times within about an hour of my crash. That >>>only takes a minute or so. >>> >>>Our local trauma center at SF General Hospital is great. I think Mark >>>Zuckerberg bought it for his wife. >> >>I once worked via an agency several month in a university hospital here >>one of the things I was tasked with was keeping that stuff running. >>We had all sorts of stuff, mass spectrometers and super conducting stuff too. >>Interesting DNA stuff, all sorts of stuff the students came up with and >>that needed electronics too. > >Universities often have an electronics shop. It ususlly doesn't get a >lot of respect but does get a lot of interesting problems. The Art Of >Electronics came out of such a shop. > >In high school, I worked summers at the physics-electronics shop at >LSUNO. It was a great experience. I had to look that up: LSU New Orleans - Wikipedia LSU New Orleans (LSUNO), known from 1974 to 2026 as the University of New Orleans (UNO), is a public research university in New Orleans, Louisiana, United States. First opened in 1958 as Louisiana State University in New Orleans (LSUNO), it was renamed the University of New Orleans in 1974 until reverting to its LSU name in 2026.  As to that original  https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&e=1 it somehow tells a lot about your personality.. I do not have a brain scan of myself... maybe good...?
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-27 08:29 -0700 |
| Message-ID | <92diblll2i1kai89lsfogmkdf9abgr6uab@4ax.com> |
| In reply to | #748278 |
On Sun, 27 Sep 2026 15:16:57 GMT, Jan Panteltje <alien@comet.invalid> wrote: >>john larkin <jl@glen--canyon.com>wrote: >>>On Sun, 27 Sep 2026 13:50:01 GMT, Jan Panteltje <alien@comet.invalid> >>wrote: >> >>>>john larkin <jl@glen--canyon.com>wrote: >>>>>On Sun, 27 Sep 2026 07:39:37 GMT, Jan Panteltje <alien@comet.invalid> >>>>wrote: >>>> >>>>>>john larkin <jl@glen--canyon.com>wrote: >>>>>> >>>>>>https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 >>>>> >>>>>Is that you? >>>> >>>>Yes. I had a head injury and volunteered for a study and got MRI'd >>>>about once a month for most of a year. It was kind of boring. >>>> >>>>I got cat scanned three times within about an hour of my crash. That >>>>only takes a minute or so. >>>> >>>>Our local trauma center at SF General Hospital is great. I think Mark >>>>Zuckerberg bought it for his wife. >>> >>>I once worked via an agency several month in a university hospital here >>>one of the things I was tasked with was keeping that stuff running. >>>We had all sorts of stuff, mass spectrometers and super conducting stuff too. >>>Interesting DNA stuff, all sorts of stuff the students came up with and >>>that needed electronics too. >> >>Universities often have an electronics shop. It ususlly doesn't get a >>lot of respect but does get a lot of interesting problems. The Art Of >>Electronics came out of such a shop. >> >>In high school, I worked summers at the physics-electronics shop at >>LSUNO. It was a great experience. > >I had to look that up: > LSU New Orleans - Wikipedia > LSU New Orleans (LSUNO), known from 1974 to 2026 as the University of > New Orleans (UNO), > is a public research university in New Orleans, Louisiana, United States. > First opened in 1958 as Louisiana State University in New Orleans (LSUNO), > it was renamed the University of New Orleans in 1974 until reverting to its > LSU name in 2026. > > The campus was on the south shore of Lake Pontchartrain, near the Pontchartrain Beach amusement park. There wasn't a lot of stuff out there in those days. I wasn't a student so they couldn't pay me. So they faked my student registration number, 20000. I guess some real student also go that number some day. They did have a library that had a set of the MIT RadLab books. I read them all. That was the first time I saw a Tektronix scope or a spectrum analyzer. >As to that original > https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&e=1 > >it somehow tells a lot about your personality.. Really? How? >I do not have a brain scan of myself... maybe good...? John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Jan Panteltje <alien@comet.invalid> |
|---|---|
| Date | 2026-09-28 06:38 +0000 |
| Message-ID | <119d21h$23a1b$1@dont-email.me> |
| In reply to | #748279 |
>john larkin <jl@glen--canyon.com>wrote: >>On Sun, 27 Sep 2026 15:16:57 GMT, Jan Panteltje <alien@comet.invalid> >wrote: > >>As to that original >> https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&e=1 >> >>it somehow tells a lot about your personality.. > >Really? How? Somehow it draws a picture in my mind of you, your attitude, your personality Same happens when just meeting a new person, but this was a bit wider. Of course I have more data from all your postings and stuff you created. 'How' is a good question. Been reading minds of people all my life, maybe it has to do with doing a lot of meditation? That is a bit like cleaning the mirror / glass you see the world through, getting the noise level of your own brain down, better observation?
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-28 17:34 +1000 |
| Message-ID | <119d5b2$249ep$1@dont-email.me> |
| In reply to | #748294 |
On 28/09/2026 4:38 pm, Jan Panteltje wrote: >> john larkin <jl@glen--canyon.com>wrote: >>> On Sun, 27 Sep 2026 15:16:57 GMT, Jan Panteltje <alien@comet.invalid> >> wrote: >> >>> As to that original >>>  https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&e=1 >>> >>> it somehow tells a lot about your personality.. >> >> Really? How? > > Somehow it draws a picture in my mind of you, your attitude, your personality > Same happens when just meeting a new person, but this was a bit wider. > Of course I have more data from all your postings and stuff you created. > > 'How' is a good question. > Been reading minds of people all my life, > maybe it has to do with doing a lot of meditation? > That is a bit like cleaning the mirror / glass you see the world through, > getting the noise level of your own brain down, better observation? More like scrubbing out the stuff you can't understand in order to let you feel better about the stuff you think you can understand Somebody who prefers the Le Sage theory of gravity to Albert Einstein's general relativity has to have scrubbed out a lot of stuff that he should have understood. -- Bill Sloman, Sydney
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| From | john larkin <jl@htigct.com> |
|---|---|
| Date | 2026-09-28 10:17 -0700 |
| Message-ID | <o78lbl158uuacng039aiece5vg3n5tk2v5@4ax.com> |
| In reply to | #748294 |
On Mon, 28 Sep 2026 06:38:39 GMT, Jan Panteltje <alien@comet.invalid> wrote: >>john larkin <jl@glen--canyon.com>wrote: >>>On Sun, 27 Sep 2026 15:16:57 GMT, Jan Panteltje <alien@comet.invalid> >>wrote: >> >>>As to that original >>> https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&e=1 >>> >>>it somehow tells a lot about your personality.. >> >>Really? How? > >Somehow it draws a picture in my mind of you, your attitude, your personality >Same happens when just meeting a new person, but this was a bit wider. >Of course I have more data from all your postings and stuff you created. > >'How' is a good question. >Been reading minds of people all my life, >maybe it has to do with doing a lot of meditation? >That is a bit like cleaning the mirror / glass you see the world through, >getting the noise level of your own brain down, better observation? > > That's a valuable skill, reading peoples' minds.
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-29 17:09 +1000 |
| Message-ID | <119fo7f$31pu8$2@dont-email.me> |
| In reply to | #748308 |
On 29/09/2026 3:17 am, john larkin wrote: > On Mon, 28 Sep 2026 06:38:39 GMT, Jan Panteltje <alien@comet.invalid> > wrote: > >>> john larkin <jl@glen--canyon.com>wrote: >>>> On Sun, 27 Sep 2026 15:16:57 GMT, Jan Panteltje <alien@comet.invalid> >>> wrote: >>> >>>> As to that original >>>>  https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&e=1 >>>> >>>> it somehow tells a lot about your personality.. >>> >>> Really? How? >> >> Somehow it draws a picture in my mind of you, your attitude, your personality >> Same happens when just meeting a new person, but this was a bit wider. >> Of course I have more data from all your postings and stuff you created. >> >> 'How' is a good question. >> Been reading minds of people all my life, >> maybe it has to do with doing a lot of meditation? >> That is a bit like cleaning the mirror / glass you see the world through, >> getting the noise level of your own brain down, better observation? >> >> > > That's a valuable skill, reading peoples' minds. Some people are convinced that they have mastered it. -- Bill Sloman, Sydney
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-28 12:54 +1000 |
| Message-ID | <119ckss$1uua9$3@dont-email.me> |
| In reply to | #748276 |
On 28/09/2026 1:04 am, john larkin wrote: > On Sun, 27 Sep 2026 13:50:01 GMT, Jan Panteltje <alien@comet.invalid> > wrote: > >>> john larkin <jl@glen--canyon.com>wrote: >>>> On Sun, 27 Sep 2026 07:39:37 GMT, Jan Panteltje <alien@comet.invalid> >>> wrote: >>> >>>>> john larkin <jl@glen--canyon.com>wrote: >>>>> >>>>> https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 >>>> >>>> Is that you? >>> >>> Yes. I had a head injury and volunteered for a study and got MRI'd >>> about once a month for most of a year. It was kind of boring. >>> >>> I got cat scanned three times within about an hour of my crash. That >>> only takes a minute or so. >>> >>> Our local trauma center at SF General Hospital is great. I think Mark >>> Zuckerberg bought it for his wife. >> >> I once worked via an agency several month in a university hospital here >> one of the things I was tasked with was keeping that stuff running. >> We had all sorts of stuff, mass spectrometers and super conducting stuff too. >> Interesting DNA stuff, all sorts of stuff the students came up with and >> that needed electronics too. > > Universities often have an electronics shop. It usually doesn't get a > lot of respect but does get a lot of interesting problems. The Art Of > Electronics came out of such a shop. It didn't. It was written as the text book for a course on electronics for physicists at Harvard taught by Paul Horowitz. I spent a couple of year working in a science faculty workshop at Nijmegen in the Netherlands and the electronics there were a lot more advanced. > > In high school, I worked summers at the physics-electronics shop at > LSUNO. It was a great experience. But a high school trainee wouldn't have got at the cutting edge stuff. As a graduate student I had to discourage a colleague from dismantling a Varian vibrating reed electrometer to dig out the 1 gigohm resistor. He was planning to measure the voltage drop across it with a regular multimeter. It took a while to get him up to speed on the input impedance of a vibrating reed electrometer. -- Bill Sloman, Sydney
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| From | john larkin <jl@glen--canyon.com> |
|---|---|
| Date | 2026-09-27 20:14 -0700 |
| Message-ID | <bkmjbl9jvdhvpnp8i2ubf12nc98il0en3t@4ax.com> |
| In reply to | #748285 |
On Mon, 28 Sep 2026 12:54:20 +1000, Bill Sloman <bill.sloman@ieee.org> wrote: >On 28/09/2026 1:04 am, john larkin wrote: >> On Sun, 27 Sep 2026 13:50:01 GMT, Jan Panteltje <alien@comet.invalid> >> wrote: >> >>>> john larkin <jl@glen--canyon.com>wrote: >>>>> On Sun, 27 Sep 2026 07:39:37 GMT, Jan Panteltje <alien@comet.invalid> >>>> wrote: >>>> >>>>>> john larkin <jl@glen--canyon.com>wrote: >>>>>> >>>>>> https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 >>>>> >>>>> Is that you? >>>> >>>> Yes. I had a head injury and volunteered for a study and got MRI'd >>>> about once a month for most of a year. It was kind of boring. >>>> >>>> I got cat scanned three times within about an hour of my crash. That >>>> only takes a minute or so. >>>> >>>> Our local trauma center at SF General Hospital is great. I think Mark >>>> Zuckerberg bought it for his wife. >>> >>> I once worked via an agency several month in a university hospital here >>> one of the things I was tasked with was keeping that stuff running. >>> We had all sorts of stuff, mass spectrometers and super conducting stuff too. >>> Interesting DNA stuff, all sorts of stuff the students came up with and >>> that needed electronics too. >> >> Universities often have an electronics shop. It usually doesn't get a >> lot of respect but does get a lot of interesting problems. The Art Of >> Electronics came out of such a shop. > >It didn't. It was written as the text book for a course on electronics >for physicists at Harvard taught by Paul Horowitz. I spent a couple of >year working in a science faculty workshop at Nijmegen in the >Netherlands and the electronics there were a lot more advanced. >> >> In high school, I worked summers at the physics-electronics shop at >> LSUNO. It was a great experience. > >But a high school trainee wouldn't have got at the cutting edge stuff. Stark effect microwave spectrosopy, Mössbauer gamma-ray spectroscopy, some superconductive stuff, played with a very early ruby laser. I was just a kid. What did you do when you were in high school? John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics
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| From | Bill Sloman <bill.sloman@ieee.org> |
|---|---|
| Date | 2026-09-28 16:58 +1000 |
| Message-ID | <119d362$22nf2$3@dont-email.me> |
| In reply to | #748286 |
On 28/09/2026 1:14 pm, john larkin wrote: > On Mon, 28 Sep 2026 12:54:20 +1000, Bill Sloman <bill.sloman@ieee.org> > wrote: > >> On 28/09/2026 1:04 am, john larkin wrote: >>> On Sun, 27 Sep 2026 13:50:01 GMT, Jan Panteltje <alien@comet.invalid> >>> wrote: >>> >>>>> john larkin <jl@glen--canyon.com>wrote: >>>>>> On Sun, 27 Sep 2026 07:39:37 GMT, Jan Panteltje <alien@comet.invalid> >>>>> wrote: >>>>> >>>>>>> john larkin <jl@glen--canyon.com>wrote: >>>>>>> >>>>>>> https://www.dropbox.com/scl/fi/yte89c83s03fghphb7thh/Brain_1.jpg?rlkey=tb71ahj2lp3zabw88ws6reofx&raw=1 >>>>>> >>>>>> Is that you? >>>>> >>>>> Yes. I had a head injury and volunteered for a study and got MRI'd >>>>> about once a month for most of a year. It was kind of boring. >>>>> >>>>> I got cat scanned three times within about an hour of my crash. That >>>>> only takes a minute or so. >>>>> >>>>> Our local trauma center at SF General Hospital is great. I think Mark >>>>> Zuckerberg bought it for his wife. >>>> >>>> I once worked via an agency several month in a university hospital here >>>> one of the things I was tasked with was keeping that stuff running. >>>> We had all sorts of stuff, mass spectrometers and super conducting stuff too. >>>> Interesting DNA stuff, all sorts of stuff the students came up with and >>>> that needed electronics too. >>> >>> Universities often have an electronics shop. It usually doesn't get a >>> lot of respect but does get a lot of interesting problems. The Art Of >>> Electronics came out of such a shop. >> >> It didn't. It was written as the text book for a course on electronics >> for physicists at Harvard taught by Paul Horowitz. I spent a couple of >> year working in a science faculty workshop at Nijmegen in the >> Netherlands and the electronics there were a lot more advanced. >>> >>> In high school, I worked summers at the physics-electronics shop at >>> LSUNO. It was a great experience. >> >> But a high school trainee wouldn't have got at the cutting edge stuff. > > Stark effect microwave spectrosopy, Mössbauer gamma-ray spectroscopy, > some superconductive stuff, played with a very early ruby laser. I was > just a kid. And was entertained as a kid would be. > What did you do when you were in high school? Survived. My first year of high school was local in Burnie, Tasmania which is still a very small town, but back then it only had 15,000 people and was dominated by the pulp and paper mill, now closed down. There were some bright kids in my high school class, and some good teachers. Two of the kids in my year went on to do Ph.D.s in chemistry at the University of Tasmania. Then the paper mill paid my father to send me off to a boarding school in Launceston which was crap and heavily infested with farmer's sons, some of whom were quite bright, but only interested in farming. The theory was that since the boarding school was expensive it had to be good, but it wasn't. I did well enough on the external exams to qualify to get into the University of Melbourne (which was a much higher prestige institution than the University of Tasmania) where I did pretty well, but high school was pretty much a missed opportunity. -- Bill Sloman, Sydney
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| From | legg <legg@nospam.magma.ca> |
|---|---|
| Date | 2026-09-26 10:25 -0400 |
| Message-ID | <s0lfbllhloov6ch4v33mc1l22p1bbulq9t@4ax.com> |
| In reply to | #748188 |
On Fri, 25 Sep 2026 07:38:00 -0700, john larkin <jl@glen--canyon.com> wrote: >On Fri, 25 Sep 2026 12:28:01 +0200, Jeroen Belleman ><jeroen@nospam.please> wrote: > >>On 9/25/26 11:59, John R Walliker wrote: >>> On 25/09/2026 08:38, Jeroen Belleman wrote: >>>> On 9/25/26 09:09, Bill Sloman wrote: >>>>> On 25/09/2026 4:55 am, john larkin wrote: >>>>>> On Thu, 24 Sep 2026 07:54:55 -0400, legg <legg@nospam.magma.ca> wrote: >>>>>> >>>>>>> On Wed, 23 Sep 2026 21:42:35 +0100, liz@poppyrecords.invalid.invalid >>>>>>> (Liz Tuddenham) wrote: >>>>>>> >>>>>>>> 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. >>>>>>>> >>>>>>>> I had some relevant experience yesterday: >>>>>>>> >>>>>>>> I was working on a radio transmitter with a 750 H.T. rail and had >>>>>>>> switched it off to make some changes to the circuit. As I leaned >>>>>>>> forward with my hand on the chassis, the palm of that hand touched >>>>>>>> the >>>>>>>> H.T. tag on a tagstrip and I received a painful elecric shock and >>>>>>>> some >>>>>>>> superficial burns. >>>>>>>> >>>>>>>> It appears the discharge resistors in the power supply had gone high >>>>>>>> resistance and were taking a couple of minutes to pull the 750v rail >>>>>>>> down to 100v. Given the time interval between switching off and >>>>>>>> getting >>>>>>>> the shock, I estimate it must still have been around 700v from a >>>>>>>> couple >>>>>>>> of 100uf capacitors in series. >>>>>>>> >>>>>>>> I don't have any suitable discharge resistors in stock and I and >>>>>>>> have no >>>>>>>> intention of doing their job for them a second time, so I have >>>>>>>> glued a >>>>>>>> strip of plastic along the top of the tagstrip as a temporary >>>>>>>> measure. >>>>>>>> I will order some replacement resistors ASAP and am happy to >>>>>>>> report that >>>>>>>> the burn marks have almost disappeared >>>>>>> >>>>>>> Were you working alone? >>>>>>> >>>>>>> Just about the only workplace fatality I'm close to was >>>>>>> a tech at Varian. Alone in the plant, he bypassed safety >>>>>>> interlocks on a TWT supply test cage to speed up his job. >>>>>> >>>>>> >>>>>> Varian was our biggest customer for many years, the NMR division. >>>>>> >>>>>> Other technologies displaced NMR. The superconductive magnets were too >>>>>> expensive. Agilent bought Varian and killed the NMR operation. >>>>> >>>>> The local hospitals are still full of Magnetic Resonance Scanners. >>>>> The Nuclear tag worried patients so it got dropped from the name. >>>>> >>>>> If Varian lost money on the operation, they were probably doing >>>>> something wrong. Super-conducting magnets are expensive, but other >>>>> manufacturers still seem to be making money by building and selling >>>>> the technology. >>>>> >>>>> <snip> >>>>> >>>> >>>> What technologies _displaced_ NMR? > >Ask Professor Google. > >>>> >>>> Jeroen Belleman >>> >>> Nothing has. >>> MRI scans are still the preferred technology for many investigations. >> >>That's indeed what I believed. >> >>> There are some interesting enhancements such as the use of >>> hyperpolarised Xenon for lung imaging and function analysis. >>> >> >>I see. Atoms with an odd number of protons and/or neutrons can >>resonate in a magnetic field and there are lots of applications >>of nuclear magnetic resonance other than medical imaging. >> >>Jeroen Belleman > >The Varian NMR group did a little micro-imaging (we furnished the >gradient drivers and temperature controllers) but most of the business >was analytical chemistry, not imaging. > >I think Bruker still does some analytical NMR. > >Varian should have owned the medical imaging buisiness but blew that. Probably just offered a good price for that division, by competitors. A lot of that going on in biomedical diagnostics, with increasingly off-shore fab (like everything else). RL
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