My First Geiger Counter

The Geiger Counter in all it's glory. Runs off a 9V battery as that was the old school way of powering home brew projects. I actually was only able to test it when I went to uni a few years later. I do these days have access to radioactive materials.

I lost the original schematic but here is the "PCB". I ended up using a CCFL inverter. I did try a camera flash board, but I blew that up during the development stage. A 10 turn variable resistor is used to trip the power to the CCFL inverter so the tube sits just at the threshold of triggering. The neon & meter were not part of the original design I found online.