Rare Soviet A-201 Dekatron Spinning

This is a rare A-201 dekatron from the former Soviet Union. Made in 1978, this tube is still in perfect working order today. I connected it to a spinner circuit and it runs fine in both directions. These tubes are interesting in that the glow transfer occurs on the center of the cathodes, rather than the tips. The lack of a shade ring or any other silvering of the glass makes these visually stunning. As always, the odd flicker is due to the shutter speed of my digital camera.

Category:

Science & Technology

Tags:

• dekatron
• spinner
• soviet
• russian
• rare
• a-201
• neon
• nixie
• tube
• counter
• display
• light

[mjrippe]

Yes, grounding pin 9 in my setup did extinguish the glow so that makes sense. Thanks again!

[hp2114b]

We have also ran them in reverse polarity, it doesn't seem to harm the tube, at least in the short term. I don't have the datasheet in front of me, but I think pin 9 is attached to some sort of control grid which we suspect may be used for digit blanking. The A201 was intended as a Nixie driver, thus having non-direct viewability, slow speed and polyatron polarity. The extra pin will indeed extinguish the glow, so digit blanking seems like an obvious function.

[mjrippe]

Hi Vintage Tech. Folks! Love your web site and your videos. You are correct, of course that I am running this reversed. It looks really cool this way and I don't think it will harm the tube (please correct me if I am wrong). Can you tell me what pin 9 is for? I left it disconnected.

[hp2114b]

The A201 isn't a dekatron, it's a polyatron, which has a central cathode with surrounding anodes. You're running it in reverse polarity, the glow should be in towards the center of the tube, rather than out on the anodes.