nixie tubes

I finally received a batch of 1n-14 nixie tubes that I purchased from ebay for a future clock project. The tubes need a power supply that can supply 170 volts DC, which I didn’t have, so I built one.

I came across a few switching designs online and I settled on the one from here, mainly because I had most of the parts on hand. I made a few changes from the schematic which I’ll detail below.


My changes (based mostly on parts that I had available):

L1 = 150uH
D1 = BAV21
T1 = IRF610
RSENSE = 1 ohm
C4 = 10uF
C6 = 470nF
VR1 = 10k ohms

I built the circuit on a piece of perf board with screw terminals for the inputs/outputs.


It worked pretty well from the start. I was getting 181.5V DC during my first run.


From 3.6 volts in, I was getting the full voltage. I will run it on 12 volts during actual use. (Ignore the messy desk.)


I plugged one of the tubes into a breadboard and just hardwired the power supply to the anode through a resistor and one of the cathodes and tried it out.


It works!


Now, to give it some logic. I wired up an MPSA42 transistor for each cathode and connected them to a bcd to decimal converter. I then put together a quick arduino sketch to scroll through the numbers. It was a bit overkill, but its what I had laying on the desk at the time. I just about ran out of jumper wires.



Well, the power supply seems to work and the tubes look okay. Next step is to design and build an actual clock.