A-101 dekatron: Minimum anode voltage ?

[gregebert]

Anyone know the minimum anode voltage required for reliable operation at low speeds (below 1kHz) ?

The datasheet is in Russian, and I can't decipher some of the specs that appear to be 375v, 425v, and 450v.

I've been running one in my big clock at 440V for years now, with no problems, but I need to run it lower in my next project (long story I wont repeat here). I'm more interested in proven designs that have run for years, rather than some experimental results. Thanks in advance.

[Bill van Dijk]

I have the following in my records:

 

A-101 Decatron

 

Brand: Anode, Dyatkovo, Russia

Substitutes: -

Counting: direction bidirectional

Operation: double pulse

Sort: sel

Base: RSH30

Socket: PL30-2p

Counting steps: 10

Number of guides: 2

Gas filling: Neon

Tube diameter max., mm: 34

Tube height max., mm: 76

Max. counting speed, kHz: 1

Supply volt. min., V: 425

Supply volt. typ., V: 450

Maintaining voltage min., V: 130

Maintaining voltage max., V: 170

Anode/cath. current min., µA: 300

Anode/cath. current typ., µA: 400

Anode/cath. current max., µA: 450

Guide bias volt. min., V: 36

Guide bias typ pulse op., V: 40

Guide bias volt. max., V: 44

Guide signal voltage pulse, Vp: -150

Cathode resistor typical, kOm: 33

Output voltage, V: 20

Reset pulse voltage min., V: -150

 

Hope that helps, it seems 425V is the minimum recommended.

Bill

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[gregebert]

Thanks. Looks I'll be using a voltage-tripler instead of a doubler.   Meh, another PC board I need to crank out....

[threeneurons]

As the translation shows, 425V is the recommended minimum supply. But remember Soviet tubes seem to be spec'd conservatively. I guess they didn't want end up in the gulag !

After tinkering with them for a while, I found the A101 to be a particularly forgiving dekatron. I've run them with a 350V supply, and they run well. But, that's also  pulsing at a low frequency, and only a short term test. It may misbehave at high frequency (>1KHz), and over time. At whatever reduced voltage you use, make sure the current stays higher than 300uA. Also, that supply (and bias voltages, too) assume cathode resistors, which raise their voltages (sometimes), by 20 to 35V). If this is a modern circuit, you may be able to subtract that drop from the supply requirements.

Note, most neon (orange) dekatrons have a sustain voltage ~190V. I think I measured the A101 at less than that.