Low cost 60V reference voltage - Page 1
Forum section: electronics / general

author: babysitter
author_rank: Frequent Contributor
timestamp: July 17, 2018, 11:00:19 pm
content: Dear fellow volt-nuts,I finally found a good job for those cheap, lying mains testers:Just attach a third wire between the neon lamp and the resistor and enjoy stable 60.000 mV! This absolutely new method of voltage stabilisation was presented by yours truly at the local makerspace.

author: thermistor-guy
author_rank: Frequent Contributor
timestamp: July 18, 2018, 12:47:51 am
content: Quote from: babysitter on July 17, 2018, 11:00:19 pmNeon (and similar) lamps have been used as zener-like shunt regulators for quite a while:https://en.wikipedia.org/wiki/Neon_lamp#Voltage_regulationIt's a good idea, though. Cheap and effective.

author: babysitter
author_rank: Frequent Contributor
timestamp: July 18, 2018, 06:48:07 am
content: Of course I am aware of VR tubes (was playing with a 0G3 a few months ago) which employ the same process, I was just joking about it being new.

author: Wolfgang
author_rank: Super Contributor
timestamp: July 18, 2018, 11:10:53 pm
content: Im aksing myself if you are aware of the fact that neons have a voltage tolerance of a few Volts, not millivolts ...

author: borghese
author_rank: Regular Contributor
timestamp: July 19, 2018, 05:00:48 am
content: You have also a sigificant overvoltage before the lamp discharge

author: markce
author_rank: Regular Contributor
timestamp: July 19, 2018, 04:52:42 pm
content: Still have a working 3 1/2 digit Philips DVM from 1971 with ZZ1000 as reference. That is 81V +/- 1.5%, 15ppm/C

author: iMo
author_rank: Super Contributor
timestamp: July 19, 2018, 05:30:57 pm
content: From 26:52

author: Wolfgang
author_rank: Super Contributor
timestamp: July 19, 2018, 06:06:41 pm
content: The tempco is not bad at all for the 70ies, but +/-1.5% accuracy is not overwhelming. What about drift and lifetime ?

author: babysitter
author_rank: Frequent Contributor
timestamp: July 19, 2018, 06:33:40 pm
content: I used it to show a relative newcomer to electronics, making extensive fun of the ubiquitility...ness yet uselessness of those things. I always stress that you shouldn't use it to test for mains but give acceptable screwdrivers. Also, extra points for a voltage tester labeled by the Wau Holland Foundation...Shortly before midnight.Quote from: Wolfgang on July 18, 2018, 11:10:53 pmYes, of course. Still, I was able to prove my point, varying the supply about a dozen volt gave just a few hundred mV variation on the "oh-so-professional DMM."Quote from: borghese on July 19, 2018, 05:00:48 amI know. And the light dependency. And possible radioactive start-boosting agents.And I like the ways things have been done in the past.

author: Wolfgang
author_rank: Super Contributor
timestamp: July 19, 2018, 07:12:24 pm
content: A small sip of nostalgia from time to time is probably not harmful.

author: markce
author_rank: Regular Contributor
timestamp: July 19, 2018, 07:22:21 pm
content: Quote from: Wolfgang on July 19, 2018, 06:06:41 pmRegular calibration is needed. Drift is 'only' 3700ppm for the first 1000h.Expected lifetime is 30000h.

author: Wolfgang
author_rank: Super Contributor
timestamp: July 19, 2018, 08:09:23 pm
content: What were the alternatives in the 70ies ? I guess heated references ? Or something else like Silver cells ?

author: markce
author_rank: Regular Contributor
timestamp: July 19, 2018, 08:50:33 pm
content: The PM2422 DMM is from 1971, but is a development from the late 60's.In 1968 Valvo announced the BZX48 silicium reference diode, which is 6.5V, 10ppm/C

author: babysitter
author_rank: Frequent Contributor
timestamp: July 20, 2018, 08:22:28 am
content: I've got a old Fluke differential voltmeter in the basement, old enough to be manufactured by John Fluke himself. It has a Weston element as internal reference and you use this by means of a "cal. switch" to adjust the +500V rail that is used to generate voltages by means of a divider. The 500V is derived from a +85 voltage regulator tube employing glow-discharge, btw.The weston element is a tasty slur of hazardous heavy metals and their salts in a fragile glass envelope, giving relatively stable 1,something volts. The omniscient landfill called internet gave mercury cells as another type of reference battery acceptable for some uses like light meters.