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Where do people get a high voltage power supply (about 300V) cheaply?

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Killa-X

Mon May 28 2012, 01:50AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
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Posts: 1039

I use to use a flyback driver to charge on a flyback core i manually wound. Now I just use voltage doublers or triplers. Depending how big your capacitors are on the doubler, will change how fast it charges your bank, and how many amps you pull from the wall, if 120VAC is an option. If not, ZVS flyback driver is my alternative for portable.

Yanom

Mon May 28 2012, 02:13AM

Registered Member #4659 Joined: Sun Apr 29 2012, 06:14PM
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I got an original charging circuit from a camera, and it works! However, I accidentally placed a wire accross the two electrodes of the capacitor when it was fully charged, discharging it instantly. I was wearing lether gloves, so it didn't hurt me, but boy did it make a noise!

Killa-X

Mon May 28 2012, 06:08AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
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Posts: 1039

Works. Some of those circuits you can modify, the flash ones, so they charge faster by removing 50% of the circuitboard. I use to parallel 5-6 of them to really charge a bank quickly off an AA battery or two. Those batteries were shot dead after a few charges, due to charging a rather large bank.

Yanom

Mon May 28 2012, 01:56PM

Registered Member #4659 Joined: Sun Apr 29 2012, 06:14PM
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Posts: 158

Killa-X wrote ...

Works. Some of those circuits you can modify, the flash ones, so they charge faster by removing 50% of the circuitboard.

I'm trying to do that. I found the circuit diagram:

Dcschem

But looking at the circuit board, it's hard to distinguish what parts from the diagram are what parts on the board. They're all so small, and wired up in a really convoluted pattern.

brandon3055

Mon May 28 2012, 02:05PM

Registered Member #4548 Joined: Mon Apr 23 2012, 03:52AM
Location: tasmania
Posts: 271

It looks like you only need the transformer the 220ohm resistor the diode and the transistor if you can find all those you can just desolder the rest (you don't need to cut the circuit board unless you want to make it smaller)

Tetris

Mon May 28 2012, 03:58PM

Registered Member #4016 Joined: Thu Jul 21 2011, 01:52AM
Location: Gainesville, FL
Posts: 660

Wire up the output of the boards in parallel, so it will be able to deliver more current. Wire the input of the boards in parallel, so it has the same voltage across each of them. Find a 1.5V DC power supply. Not sure how that would turn out. I feel your pain as the high schooler with no money. What I do is rip apart things in my house that my parents don't need anymore to get missing components, power supplies, and tons of other things.

Killa-X

Mon May 28 2012, 04:51PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
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Posts: 1039

Destroyer of mosfets wrote ...

It looks like you only need the transformer the 220ohm resistor the diode and the transistor if you can find all those you can just desolder the rest (you don't need to cut the circuit board unless you want to make it smaller)

You need the little silver / yellow film capacitor too. If its a 4 wire transformer you can desolder and solder without a pcb as you mentioned :)

Yanom

Mon May 28 2012, 07:18PM

Registered Member #4659 Joined: Sun Apr 29 2012, 06:14PM
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Posts: 158

Killa-X wrote ...

You need the little silver / yellow film capacitor too. If its a 4 wire transformer you can desolder and solder without a pcb as you mentioned :)

looks like this but silvery-yellow-green?
Accurate Polypropylene Capacitor

What is the purpose of that one?

Neet Studio

Mon May 28 2012, 07:18PM

Registered Member #4037 Joined: Fri Jul 29 2011, 03:13PM
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Posts: 86

Actually looking at the relaxation oscillator for the neon light 3.9M + 0.002uF, I would be very surprised if removing it would dramatically speed up the charge time at all. A 3.9M ohms resistor is in series, so at most 77uA of current is drawn at 300V even if you short the 0.002uF cap or hold down the flash button. The average current is going to be like 1/2 of that.

Let's say it takes 10 seconds to charge up the 1 cap. Assuming the charge current is linear (not quite, it usually taper off near the end)
Q = C * V for 160uF, 300V, the charge current would be 4.8mA on average. 77uA is only 1.6% of that. This is not a significant improvement.

Having it in place would at least give you some idea that there is at least 100V or so in the cap, so might not be such a bad thing as a warning light. If the cap was at a higher voltage, it would work as a bleeder for discharging. Even when the light is out, there might be a charge there depending on whatever minimum voltage the neon would work at so still be careful!

The rest of the stuff flash tube, trigger transformer etc actually won't drain power.

Pinkamena

Mon May 28 2012, 08:31PM

Registered Member #4237 Joined: Tue Nov 29 2011, 02:49PM
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Posts: 117

It's pretty simple. Use four diodes to make a rectifier, connect to mains. It'll give you 240V RMS if you're in europe.

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