Nixie clocks for a contest

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I am working hard on a clocks for a contest called “When Prague Meets Shanghai” (more about contest here: WPMS). This is a first oportunity how to present working tubes in a real product.

The clock electronics is based on Arduino, uses precise DS3231 RTC and as a HV supply I used high end PSU from Yan Zeyuan.

So, I made two nixie tubes with 50mm numbers, they didn’t contain getter. Pressure in both tubes is 30torr, so the glow is slightly fuzzy, however I chose that pressure so that I would be able to achive more uniform glow at lower voltage and current. Striking voltage after aging process is around 150V, I use 170V supply with 20k current limiting resistor. Current is around 4.5ma, both tubes and PSU stay cool.

Visualization..

Tubes running at 4.5mA.