Edit: Changed subject from just HV switches to tube tester..., as I'm also interested in comments besides the switches.
I might build one (and I do know an EE who would take a final look, ensuring I'm not doing something dangerously stupid).
There are quite some manual switching & measuring tester projects out there for me to know what, and how, to measure.
But I'd rather not do manual switching of pinouts etc.
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Howdy!
I found this little bugger here:
https://docs-emea.rs-online.com/webdocs/166e/0900766b8166ed01.pdfDo things like that exist also in forms which can withstand 400V (really, not abs max)?
Actually some 1-to-8 analog mux with fewer pins than an array of 1:1 swichtes would be even better.
Background:
I have looked at vacuum tube tester projects recently.
There are those manual ones, either with a set of heavy duty "chickenhead" rotary switches to map different pinouts of various tube types onto a measuring/testing circuit's terminals.
Or wilder constructions with lots of banana jacks to establish the connections with cable salad. (my least favorite variety.)
Then I saw a project with a bazillion relays, doing everything in an automated way.
Mmmmmh, I like automated.
Attention, now (latest) begins non-EE crazytalk, of a big kid who likes to tinker...
...but who has built tube radios as a kid, from 1950's books circuits (but in the 90's), which worked, AND survived to tell about it!
So I thought, hey, instead of several bucks per switching unit of something like 9 x 7 = 63 units (assuming noval socket, and mapping wires to a "virtual" pentode socket of 7 pins for measuring, where I assume arbitrary pinouts for valves - maybe it can be less because there are pinout permutations which do not exist... I'm "familiar" with only a couple of tubes).
I saw that there are MOSFETs which can do 600V and 3A and such, at 50cents/piece at low volume purchase - much cheaper than relays. Wouldn't that be something.
Then I thought, hey, are there maybe HV analog mux ICs, and I found the linked switch IC, but none that can do 400V.
For most tubes I know so far I need at least 250V, and I saw other projects going to 400V, so I guess it'd be a good idea to cover that.
That would be really sweet, instead battallions of single MOSFETs, eh?
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Edit:
Other aspects of such a tester - so far I heard suggestions for:
- generation of anode and grid HV using a Royer Converter like Fig.4 here, and replace the regular pot with a digipot: https://www.analog.com/media/en/technical-documentation/application-notes/an118fb.pdf
- measuring the anode current with this kind of IC: http://www.ti.com/lit/ug/tidu833/tidu833.pdf
- an microcontroller shall be the master of the whole thing, switching things according to selected type, measuring stuff with ADCs, maybe check for user errors (e.g. selecting wrong type) by doing "all" possible tests before engaging high voltage, e.g. check whether anode and cathode pins are not swapped with the filament pins and other un-nice scenarios; record characteristic curves, compare them to database of what should be (or show closest match for tube where type is not readable on the outside) and whatever you can think of (and I feel like implementing, lol)
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Comments?
Products?