Hi Marcin, I actually found one source which confirms the use of the screen (grid or trigger electrode) in multiple-anode cold cathode tubes for just that purpose! The article is named "A study of coding with multiple-anode glow discharge tubes" and was published in The Radio and Electronic Engineer September 1964: http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=5266726&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F5266378%2F5266723%2F05266726.pdf%3Farnumber%3D5266726 . Note that the article does not speak about counting tubes, just trigger tubes with multiple-anodes. The article is written by H.E. Seifert which also wrote an article on the glow-thyratron, the Cerberus GT21 (also Mullard Z865W) which is used together with the GCA10G/GSA10G /Z572S/Z573C) as coupling tubes. There they show a way of using multiple-anode trigger tubes to do coding/decoding of signals where the anodes from more than one trigger tube is connected together and the screen/grid electrode from each tube is used to do the coding/decoding by switching on the requird trigger tubes as needed. The trigger tubes and Nixie are driven by half wave rectified AC voltage which means that the trigger tubes switches off when there is no voltage across them and the Nixie, they would have stayed on if they were driven by DC voltage until the DC voltage had been removed. The article ends with a picture showing a combined tube which involves both the trigger tubes and the indicator part, which looks like a 7-segment display! I know I have seen a patent with that type of tube but I can't find it right now. Last summer I wrote about two patents covering combined units with Nixie displays and a control unit which was either a Dekatron (the German patent) or a set of trigger tubes (the French patent by Elesta) here: https://groups.google.com/forum/?fromgroups#!searchin/neonixie-l/combined$20dekatron/neonixie-l/VScgxdUDZ6E/IfvX3761DhoJ , looking at the French patent it is using a grid to control the electrode structure to allow different figures to be display. I haven't checked the English translation of this patent fully but what I checked talks about a design that uses a trigger tube with control electrodes - grids. I'm not sure if all of this is applicable to the A-201, but it is fascinating nonetheless! /Martin
On Sunday, February 17, 2013 8:57:45 AM UTC+1, marcin wrote: > On one Russian forum, sorry didn't save the source, one guy claimed the > screen function is to quickly blank the connected nixie. > Marcin > > On 16/02/2013 23:59, Jon wrote: > > The most curious thing about the A201 is pin 9, whose function > > translates as 'screen' or 'shield'. It's not shown in use on any circuit > > diagram I've seen for this tube. > > The only other counting tube I'm aware of with such a structure is the > > G10/241E Nomotron (and of course the 11TU7 lookalike). The datasheet for > > that also does not discuss the function, but specifies that it be set at > > a +90V bias. J B Dance (Electronic Counting Circuits) suggests that the > > purpose of the shield is to confine the glow to the required part of the > > tube. It could well be a similar function for the A201. In the polyatron > > configuration, unlike the dekatron, the discharge glow is associated > > with the common electrode rather than the electrode which is spatially > > specific for each counting position. This may mean that additional > > measures like the shield are required to stop the glow spreading across > > the common cathode and degrading the counting performance. > > It's interesting that Marcin's datasheet says that the glow is purple, > > whereas every A201 I've ever seen is neon-orange... > > Jon. > > > > -- > > You received this message because you are subscribed to the Google > > Groups "neonixie-l" group. > > To unsubscribe from this group and stop receiving emails from it, send > > an email to [email protected] <javascript:>. > > To post to this group, send an email to > > [email protected]<javascript:>. > > > To view this discussion on the web, visit > > https://groups.google.com/d/msg/neonixie-l/-/7XzdWqtrjsUJ. > > For more options, visit https://groups.google.com/groups/opt_out. > > > > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/IGJoZiGw7AkJ. For more options, visit https://groups.google.com/groups/opt_out.
