30kv .3mA DC power supply tips?

[Fungiwrangler]

Hello, I interesting in making a high voltage power supply for capillary electrophoresis. Not much power is required and the DC does not need totally noise free so I figure this gives me a lot of flexibility. I would love the ability to adjust the voltage at 5kv increments in maybe a 5-30kv range. It would be great if the voltage could be adjusted/turned on+off using a microcontroller whether I need analog output or to add a relay/transistor it doesn't matter. Also I would prefer to power this supply using either 5 or 12V DC.

Can anyone point me in the right direction? I bet there are some exotic circuits that this would be perfect for.

I am looking for something that uses less then 20$ worth of parts, or a commercially available unit for around that price.

Any help would be great.

 

[Fungiwrangler]

I have been looking into a Cockcroft–Walton circuit for this. Apparently it can be run with either AC or pulsed DC.

Running on of these on 12V DC would be a huge pain, around 1000 stages are needed.

Does anyone know of a very low cost high voltage AC generator that runs off 12V that is commercially available?

 

[Carl Pugh]

If you had around $200.00 availiable then maybe you could purchase a ready built supply or the parts to build one.
You could check on ebay and you might find a power supply for $20.00.

 

[Squid1775]

I would suggest using an inverter. You can use your house socket (120 VAC), a transformer (probably a step-up or some other high voltage transformer), some transistors, and switches.

**Safety Warning**
Very high voltage! It can kill you!

Using that stuff would be a hack job though for $20 or less. The specifics that you request (5KV increment) requires custom design which is going to cost more whether you do it yourself or you find a commerical product. Your SAFEST bet is go buy it commerically because then it will most likely be UL listed.

 

[cmb]

This is TV line output flyback territory. You can usually pick one up for a couple of bucks, then build a switching circuit.

There are diy-level instructions at http://www.blazelabs.com/e-exp03.asp , where they are suggesting getting 2.2mA at 30kV from one.

If you can wait 8 months, then [if anyone is interested] I'll pin up here a patent of mine that is currently filed but not published that can also accomplish your requirement with much less effort. (I have a 1 to 20kV 5mA prototype I've been using for HV work for the last year, which I built from new commercial stock parts for a total BOM = 12 euros, and which you can stack in parallel or serial with the same again as it is a DC uncoupled output.)