MightyOhm.com

Can you tall me he make and part number for the L1 inductor used in your Geiger Counter kit?

I've been experimenting with switching power supplies and I tried to replicate the one used in your Geiger Counter kit for used as a small CRT power power supply. I suspect I'll need a design with more power for my final application but, right off the bat, I was only able to get about 160 volts with my copy of your design. I had expected to get around 400 volts, so I suspect my choice of inductor is the issue, as every other part is the same as your design used.

Wayne

It's a Panasonic ELC-09D103F. What are you using for Q1 (the HV switching transistor)?

Thanks for the prompt reply. I'm using an FJN3303 as Q1, which I think is the same as what your parts list specified.

In looking over some of the other posts, I'm beginning to wonder if the problem is that I'm not measuring the actual voltage due to input impedance limitations on my DVM. I hadn't realized that the output current on this step up design was so low. I'll have to try using a null bridge approach, or some other high impedance method to get a better read on the true voltage. In any case, I'm going to have to step up the the available current quite a bit in order to drive my 1EP1 CRT.

Wayne

Take a look at the Resonant Royer circuit: http://www.edn.com/article/472194-High_ ... erters.php

Eric Schlaepfer used it to make a CRT driver. I can't seem to find any information online, however. His website is http://tubetime.us/