[cctalk] Re: Digital or Pulse Electronics with Trigger tubes?

On Mar 8, 2026, at 5:18 PM, Holm Tiffe via cctalk <cctalk(a)classiccmp.org> wrote:

<snip> ..so I have an working ring counter here next to me on a breadboard. :-) There is still an MPSA42 used as an pulse former in the clock circuit that I want to change agains a trigger tube. I need an Ide of an circuit that gets triggered on approx. 30-40V and outputs an rectangle pulse of lets say 60V and 10-30µs duration to properly trigger the ring counter, using possibly only one trigger tube. I think no one knows that for now..but I'm very grateful for links to older literature on this topic. approximately in 2000 I'm parted out old hp tube counters, the displays where "thermometer Displays using 10 pcs. of neon lamps, one for each number. The counters used 4 12at7 type "digital" tubes (don't remember the exact type for now) with biquinary output to the neon lamps. Later hp counter modules used the very same schematics and the neons and one hybrid photoresistor module in front of the neons as decoder to drive nixie tubes. I've tried it already in the past with the neon bulb ring counters.. a cheap photoresistor in a balc schrink tube that was put onto the neon lamp can switch a nixie..it works flawlessly. Tried this on the TX4b .. works too. :-) ..other schematics ad an additional trogger tube for each nixie cathode..the effort pretty much explodes... Hope someone can help with some hints or links. Regards, Holm