Dekatron 60 sec reset

[Jarod Findley]

Hello all first time poster I'm new to electronic design although I have basic understanding. I have attached a what I believe to be sound logic to use a single thyratron as sort of memory cell. My idea is that the first pulse from the dekatron will send the thyratron to a high state and allowing the cap to get a negative charge. When the next pulse comes in it hits the thyratrons grid again but also charges the cap to a high voltage state. Then causing the cap to discharge its current to ground quickly pulling the thyratrons current to a unstable state and it to loose gas charge. This spike can then be sent at the same time to the reset of the dekatron if it was lets say in the forth position of a 10 count dekatron making it reset at 14. I want to use this circuit on a a101 dekatron so that with a signal dekatron I can count to 60 effectively.  I would like to use this to device 60 hz in 1hz with a signal state and have a dekatron for the seconds counter of a clock. I don't have access to any equipment to test this design yet so any feedback is apricated. I'm also wondering if anyone has a circuit design that functions in this way. I ideally would like to only use one thyratron to accomplish everything. 

[gregebert]

Without seeing the rest of the circuit, I don't see how the transistor will ever turn on. Before building any circuit, it's best to simulate it with a tool such as LTspice; if the circuit doesn't work in the simulator, it certainly wont work on the bench.

Start small, such as getting a single dekatron to spin, then you can add a second one to count to 60. Once you're at that point, you will probably rethink the details of your circuit based on what you learned and measured from the dekatrons. I have a single A101 that has been spinning 24/7 for more than 10 years now, but it took some tweaking to get it to work reliably. 

[Dekatron42]

There is a nice Dekatron Clock here: http://www.959radio.co.uk/dekatron.html which uses a mix of valves and transistors with circuit diagrams, I hope you can learn from that design even if there is not much explained from what I could read.

/Martin

[Mac Doktor]

On Apr 11, 2025, at 11:20 AM, Dekatron42 <martin....@gmail.com> wrote:

There is a nice Dekatron Clock here: http://www.959radio.co.uk/dekatron.html which uses a mix of valves and transistors with circuit diagrams, I hope you can learn from that design even if there is not much explained from what I could read.

Also:

https://threeneurons.wordpress.com/dekatron-stuff/

https://threeneurons.wordpress.com/kits/

Lots of useful information. The bad news is that he's sold out of almost all of the kits except for the magic eye gadget:

https://www.ebay.com/str/tortugascuba

He told me that sales dropped sometime after COVID and they've never come back. I get the impression that this has happened to other kit sellers as well.

Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com

"Every kid starts out as a natural-born scientist, and then we beat it out of them. A few trickle through the system with their wonder and enthusiasm for science intact."—Carl Sagan, Psychology Today, 1996