Pocket High Voltage Generator Upgrade
HV Generator open output voltage – limited internally to under 200V. The red LED lit up to indicate the voltage limit has reached.
The Pocket High Voltage Generator that I made a few weeks ago proved to be a very handy tool. I have been testing Zener diodes very often since I use many Zeners in 12V to 91V range.
However I wanted to give it a bit more power so that I can test Nixie tubes clearly – the previous design can only give less than 0.5 mA through most Nixie tubes, some digits don’t lit up completely.
I made some upgrades to the components to give it a modest 2 – 5 mA (depending on the voltage) output. While still keeping the same form factor.
Upgraded HV Generator can comfortably drive Nixie tubes at 1 – 2 mA of current.
Now this circuit has enough oomph to shock you if you accidentally touch the output! Not the dangerous level, but it IS shocking. Perhaps one can use this as an electric Jack-in-the-box…
I’m sharing the PCB design of this project. Which can be purchased or downloaded via OSH Park.
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After searching through my junk box for good transistors I came up with the 2SD669A for Q2.
Another one I will try whenever I order parts is the SFT1202E.
This is a great project but I found it gives low readings for zener diodes under about 80V, changing R5 to 68k gives it about a 1 ma short circuit output which helps.
It runs great on a AAA battery.
Thanks for posting this. Nicely done.
February 7, 2019 at 3:34 am
Could you provide manufacturer part numbers or rating info for the diodes and the inductor?
Thanks!
November 25, 2018 at 7:15 pm
L1 is 9 mm or larger drumcore, at least 0.5A rated.
D1-D3 can be 1N4181 type, 100V. I know this doesn’t give any margin so you might want to use ultrafast recovery diodes rated at higher voltage.
D4 can be pretty much any zener of the same voltage.
November 25, 2018 at 10:15 pm
Thanks!
November 26, 2018 at 9:56 pm
Thanks for a very simple and interesting design! I was looking for long time for something like this to test the geiger tubes… Could you advise what needs to be changed for 400-450 V output? Specifically on the requirements for the transistors, diodes and C2, C3, C4 capacitors. Sorry I’m not a specialist on HV… Thank you very much in advance.
November 25, 2018 at 3:36 am
400-450V… That’s a bit higher than I’ve ever needed. I think you can add more multiplier stages to get that voltage, if you only need a couple of milliamps.
Please look at the MOSFET version of simple HV generator circuit posted here: https://blog.theledart.com/blog/archives/2115
This circuit needs at least 10V input, but you should be able to get around 400V by adding a capacitive doubler.
November 25, 2018 at 10:04 pm
Look interesting !
i use HV857 for high voltage but this schematics easy and cheapest.
Thanks !
November 23, 2018 at 10:08 pm
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