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Month: October 2017

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.


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