Set/Reset and Carry stages for A-201 Polyatron with simplified driving circuit.

[Dekatron42]

Hi All,

Now I have finished designing and testing the Set/Reste and Carry stages for the Russian A-201 Polyatron using the simplified driving stage I published a few days ago.

This design also relies on the same Russian patent, SU609215, for the simplified driving stage as it uses that driving stage for the Set/Reset stage, it also uses the design found at Radiokot.ru in that it uses the -160V line for the driving stages and Carry stage.

The Carry stage however is my own design and it works by checking the negative voltage change on the auxilliary anodes of the Polyatron (being the same as the cathodes of the Nixie tube) and then uses two voltage translation stages to produce a negative output pulse which can be used either as a Carry output pulse or as in the schematic being returned directly to the Set/Reset stage.

In the video you can see the polyatron counting from 0 up to 5 and then being reset and then also up to 2 and 7. The maximum frequency is determined by the deionization time at the carry position and ionization time at the Set/Reset position so it is slower than in normal counting but I could get the Polyatron to work reliably up to some 3KHz without a problem when counting 0-5.

The video can be found here: http://www.youtube.com/watch?v=R6WOqGV3sQA

Cheers,

Martin

[Nick]

More good work - great to see...

Polyatrons, seem to be just "inverted" dekatrons - everything is backwards - there are obvious advantages (less cathodes so less sputtering & "poisoning" etc.), but downside in the speed.

Are they just a side-branch, i.e. a footnote or anachronism? Were there any developments that built on the polyatron technology?

Cheers

Nick

[Jon]

On Sunday, March 16, 2014 5:56:40 PM UTC, Nick wrote:

 

Are they just a side-branch, i.e. a footnote or anachronism? Were there any developments that built on the polyatron technology?

The core advantage of the tube is really the direct drive of the display tube I think. ETL's solution to the same problem was the auxiliary anode tube (GSA10G and GCA10G) which effectively combines the two operating modes - counts like a dekatron, but drives the nixie via a separate set of electrodes. Both polyatrons and aux anode dekatrons are neat solutions, but fundamentally by the time they appeared the whole field was well on the way to TTL counters. Probably polyatrons got more use in the Soviet Union as tube technology clung on longer there.

Jon.