5kV 40uA from 120VAC

On a sunny day (Thu, 7 Jul 2011 13:12:23 -0700 (PDT)) it happened Kooner wrote in :

Any old BW TV transistor circuit should give you 15kV at that current. Just turn it down a bit :-) Must be tons of those along the road.

On a sunny day (Thu, 7 Jul 2011 23:55:40 -0400) it happened "P E Schoen" wrote in :

Old HeNe laser power supply, here I use one with volatge controlled by a PIC:

It now does only 1.5 kV or so, but you can get 5 no problem, more too. Runs of a 12 V wall wart.

Am 08.07.2011 06:32, schrieb John Larkin:

very nice! What type of diodes do you use in your multiplier?

Regards, Alexander

Those are MMBD204's. They are cheap, as I recall.

I did evaluate some VMI packaged C-W multipliers, but they had very low capacitor values and were insanely expensive.

Actually, small potted HV supplies aren't real expensive. It might have been more rational to just buy some.

John

Am 08.07.2011 15:33, schrieb John Larkin:

I had a quick look in the datsheet. Unfortunately they can only handle 300V.

'insanely expensive' is absolutely true! A couple of years ago I had to replace a 2kV diode from Philips which had been discontinued. When I asked VMI for a replacement type I thought they were joking.

Reagrds, Alexander

I often suspected that Larkin was gay. After all, he does live in San Fransicko, Californica :-) ...Jim Thompson

They overshoot to some ridiculous voltage at turn-on, so you have to be careful.

Cheers

Phil Hobbs

You said you loved me. I always thought you were a repulsive idiot.

Let the world decide.

John

That's why you use lots of them!

John

Freaking moron. I was praising Alex, not myself.

You offered to post stuff, then chickened out.

You dared me to post a C-W HV circuit, and I did, and all you do is whine.

We're discussing HV circuits, and you've sniveling.

And you didn't answer the question about why a lower-ratio transformer and a multiplier is often a better design.

Idiot old hen.

John

Hey, Jan's schematics are even fuzzier than yours!

I should send you each a Boston electric pencil sharpener.

I'm old enough to have taken *two semisters* of engineering drawing, and they pounded linework quality into us. We even had to ink our own borders and title blocks.

John

On a sunny day (Fri, 08 Jul 2011 11:13:45 -0400) it happened Phil Hobbs wrote in :

That is why the voltage feedback via the PIC, PWM modulated output. The original circuit I got the cascade and transformer from had a 555 timer :-)

On a sunny day (Fri, 08 Jul 2011 08:48:11 -0700) it happened John Larkin wrote in :

For ciruits this simple who needs a schematic?

Abuse, he gives me, and on my first Friday afternoon in my new office, too. I bought a nice Brother B-size all-in-one, and I'll have you know that my hand-drawn schematics now reproduce *beautifully*. Jan's look like the Dead Sea Scrolls after a late night partying.

So a loud and juicy raspberry to you and your hifalutin engineering school penmanship.

Cheers

Phil Hobbs

Where are those great cavitation photos?

John

I was at a hardware store (Mountain Hardware in Truckee, aka Mountain Macy's) and they had a thing that looks just like a tennis racket, but has two high-voltage grids. You swat a bug with it and it goes ZAAAPPPP!

John