Calculating Anode Resistor Values

Mac Doktor

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Jul 6, 2022, 6:54:07 PM7/6/22

to neonixie-l

I'm in the dark concerning this topic. I have a large number of sockets from NixieTester dot com to assemble and some have multiple resistors in the kit. Socket #3 comes with four different values. I realize now that the "correct" resistor isn't just a matter of 170V over the current. The correct value appears to be much lower than that.

What's going on here? Is the missing factor the resistance of the plasma itself? If so what is the formula? I can't find the data sheets for some of my tubes and I'm a bit clueless as to how to proceed. I have the Pro Nixie Tester which I can use to do real world tests but I need to exactly what I'm doing first.

Pile on.

Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com

"Would you like to see the relevant data?"—343 Guilty Spark, Halo 2

Max Di Noi

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Jul 6, 2022, 6:57:07 PM7/6/22

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Hello,

the correct resistor is calculated as 170V minus maintaining voltage (check the datasheet of the nixie, usually 140v or so) / current.

So, for a nixie that needs 2mA you would use a resistor of: (170v - 140v) / 0.002 = 15k ohm.

I hope that helps.

Max

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Mac Doktor

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Jul 6, 2022, 7:09:39 PM7/6/22

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On Jul 6, 2022, at 6:57 PM, Max Di Noi <flata...@gmail.com> wrote:

the correct resistor is calculated as 170V minus maintaining voltage (check the datasheet of the nixie, usually 140v or so) / current.

A-ha.

So, for a nixie that needs 2mA you would use a resistor of: (170v - 140v) / 0.002 = 15k ohm.

Perfect.

I hope that helps.

This doesn't just help, it REALLY helps! 8D

Why have I never heard this before? <head scratch>

Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com

"Every kid starts out as a natural-born scientist, and then we beat it out of them. A few trickle through the system with their wonder and enthusiasm for science intact."—Carl Sagan, Psychology Today, 1996

Paul Andrews

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Jul 7, 2022, 9:53:47 AM7/7/22

to neonixie-l

Assuming that the nixie tester uses 170V that is

Max Di Noi

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Jul 7, 2022, 12:48:51 PM7/7/22

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Indeed.

Terry, this is an excellent page.

https://threeneurons.wordpress.com/nixie-power-supply/

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Mac Doktor

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Jul 7, 2022, 4:09:17 PM7/7/22

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On Jul 7, 2022, at 12:48 PM, Max Di Noi <flata...@gmail.com> wrote:

Terry, this is an excellent page.

https://threeneurons.wordpress.com/nixie-power-supply/

I've been scouring Mike's site for years and I have no memory of this page. It must have seemed like more than I needed to know at the time. Does anyone have a spreadsheet for this? It would save a lot of time otherwise spent on reinventing the wheel.

Here's Marcin's Nixie Tester. Note the diagrams and formulas at the bottom. lt's beginning to make more concrete sense to me now: