Easy high voltage power supply

hv_supply

[rocketman221] wrote up one of the simplest ways to build a high voltage power supply. This one in particular was used on his coilgun. Instead of building a custom circuit, he’s using flash charging boards from disposable cameras. Six 450V 470uF caps are wired in parallel to make up the bank. Two of the charger boards are wired to one switch to initiate the charging process. Four additional boards are wired two a second switch for the second charging stage. The part cost on this is incredibly cheap and it only requires a 3.3V input to reach 450V. The writeup has plenty of warnings about the dangers of high voltage; you need to clean off all flux residue to prevent arcing across the circuit boards. Embedded below is a video of the bank being discharged through several objects.

Comments

  1. rivetgeek says:

    Whoever is doing this damned well better be wearing welding goggle since the uv light from those arcs will gladly fry your corneas

  2. EchoLynx says:

    Yea, and it’s sure not good for your camera either.

    Advantage(?)- Instant sunburn.

  3. tony says:

    I love how he just destroys a bunch of stuff with all that voltage. thats exactly what i would do. i mean eventually i’d have to do something more constructive, but i have a feeling it would take me a while to get to that point.

  4. Jynx says:

    @tony
    I wholeheartedly agree.
    and will also have to build one of these :D

  5. spikey says:

    Cool – as long as I see that kind of stuff I know that pioneering spirit is not dead.
    We all (I am ‘older’) grew up blowing things up, and only a few got hurt.
    Kudos!

  6. Frogz says:

    made 1 of these when i was a kid
    bunch of capacitors in paralell with a 2 aa camera
    (for the record, dont try to up the power with more caps on the default xenon tube, they tend to go explodey)
    a standard 10 amp wall switch is effective at dumping the entire load nearly instantly, solenoids make good cheap coil guns as well

  7. funylilman says:

    Correct me if I’m wrong but wouldn’t that be more of a high current supply. High voltage supply would be more along the lines of my flyback transformer outputting 10kv and up. While that stores and discharges a high amount of current @ 450 volts.

  8. Joe Cephus says:

    It’s too bad that the inductance of those long, thin wires connecting the caps will severely hinder his dI/dt. Short, fat bus bars are called for if he *really* wants to dump the energy in a hurry.

  9. ac7zl says:

    Projects like this are always interesting, but a few comments/concerns come to mind.

    First– what’s with the cardboard box? In the spirit of hacking, any of a hundred different kinds of metal or plastic cases could be used, salvaged from defunct appliances/electronics.

    Second– I didn’t see mention of bleeder resistors.

    Third — If discharging the caps while the charger boards are on will damage them, then you should probably rig the circuit so that this can’t occur. Use a SPDT or DPDT switch. Arrange it so that in one position, the cap bank is connected to the chargers, in the other position, the cap bank is connected to the output terminals. This makes the fault condition impossible to achieve.

    You will want a very robust switch with large points, otherwise you may end up spot welding the switch contacts together. Alternately, you could use a large relay/contactor to implement the same function. In fact, if you arrange the circuit so that the contactor is powered whenever the charger is on, then the switching function becomes essentially automatic.

    Fourth — I think this was mentioned…but if you want rapid discharge, you want to conduct the current out of the cap bank with bus bars, not with thin wires.

  10. jordan says:

    I wish people would post custom charge circuits. I rebuilt a camera charger with my own custom transformer but it refuses to oscillate.

  11. jim says:

    i wonder if vaporised aluminum foil has medicinal properties? because i would have though all signs point to no

  12. jim says:

    thought, even ._.

  13. drew says:

    i built one of those before if you stack the chips on top of each other it saves alot of space since its a parallel circuit you can just link them together like your stringing popcorn for a Christmas tree

  14. Crash Override says:

    Reminds me of arc welding, although it is more controlled, this is still an amazing example of what power raw electricity possesses. Rivetgeek and EchoLynx are right though that UV flash can blind you pretty fast, and I have ruined a few $3,500 camera lenses for not using an ND or UV filter when filming instructional videos on how to weld properly.

  15. hack says:

    Hehe good thanks Eliot

  16. Ninja says:

    @ crash override

    What was it…. mess with the best, die like the rest??

    lul

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