5kV 40uA from 120VAC

If you only need a few, find some surplus copy machine HV supplies. There are tons around.

Or get a surplus CCFL supply and rectify the output.

If you really want to build it, I'd suggest a flyback transformer blocking-oscillator sort of thing followed by a C-W multiplier.

Or an old teevee flyback+rectifier assembly. Cheap but big.

John

Those are only slightly above 1kV but most likely less because 40uA is loading it.

You can get ones that are just a cubic-inch or two, and the rectifier is already built in. One source would be an old portable CRT TV, the kind with the postcard size B/W screen.

CCFL supplies put out at least a couple milliamps. I would suggest using one of those with a voltage multiplier, maybe a Cockroft Walton one. CCFL supplies in my experience have AC output.

Yes, you can do that. However, you need numerous (fast) HV diodes and HV capacitors and that quickly gets old.

I'd try that first. But not if this is for a product that has to run in production for many years. Those TV flybrack transformers are headng towards lalaland, on acount of all those flat screens.

Another low-tech solution: The transformer out of a bug zapper. Overkill, but cheap. Alternatives would be moped ignition coils and electric fencing magnetics.

I've done that, works great. Use the HV caps they come with for the first stage. On the ones I've used, you can remove the grounding strap from the secondary, which helps with voltage multipliers.

Cheers

Phil Hobbs

It can be done with 3 parts and meet or exceed all the given specs. Art

You need multipliers for 5 KV from TV / monitor flybacks?

Please tell us how. Preferably, something more convenient than some inconvenient transformer, a diode rated for more than the peak-to-peak voltage coming out, and a capacitor that could be oddball to get or might be homebrewed.

Preferably also something that delivers a lot less than 50 mA RMS to a spark gap whose breakdown voltage is 1 or 3 KV - test by putting a low voltage incandescent lamp in series with the spark gap. If RMS current gets around/over 50 mA, especially 100-plus mA, then there is significant electrocution hazard if you make a bad move.

Yeah, a transformer, a diode, and a capacitor. Got a good source for the transformer?

Cheers

Phil Hobbs

As long as you're adding parts availability, safety, and test requirements which the OP didn't specify, how about also tacking on efficiency, max ripple, and doesn't cause cancer in the state of California? ;~)

A transformer, a diode, and a cap fit the stated requirements and are readily available in any microwave oven. Art

Microwave oven. Max weight and volume were not specified as a requirement. Art

This:

:-)

Does the cap get 5 KV DC across it? Does it get 5 KV DC across it in all microwave ovens easy to find in appliance stores, thrift shops, and in the trash?

I just tried one that my brother gave me, of a largish size one made for 120V input. I found its voltage gain to be only 20.5 - good for 2460 volts AC or not quite 3500 volts DC.

I went into a breakfast restaurant in CA on Saturday. I kid you not there was a sign at the entrance saying, "This building contains substances know to be hazardous by the State of California".

Duh! Someone ought to line up all the politicians and bureaucrats in Californica and treat them to a Valentine's Day Celebration ;-)

I also noticed they impose SALES TAX on gasoline. No wonder I tend to lump all Californicators into the ignorant column ;-) ...Jim Thompson

Are you anticipating that hell is going to freeze over ?:-) ...Jim Thompson

The cap & diode form a doubler on the secondary. Huge ripple but that wasn't specified. Art

All 50 states have sales taxes on gasoline.

Now I'd like to see a schematic how you double the voltage using one transformer, one diode and one capacitor :-)

Isn't that what car companies are now trying? Delivery of a spare tire inside the new car wasn't specified ...