Measuring the ~10 kiloamp output of a large capacitor bank

[Norman] put together a rather impressive 22,500 uF capacitor bank. In addition to find things to torture with the strong magnetic field generated by a sudden discharge, he’d like to measure the current pushed from the device. He’s found a way to do this using a digital storage oscilloscope. To protect the oscilloscope [Norman] built his own interface box that includes a 50x voltage divider, and interfaces a current sensor called a Rogowski coil. When it comes time to run the experiment, he turns the safety lock-out key on the bank charger, then discharges the stored potential with the flip of a switch.

Take a look at the video after the break to see soda cans and hard drive platters mangled by the device. The oscilloscope measures the output near 10 kA, giving [Norman] the data he set out to capture. He’s entered this project into the Tektronix contest where it’ll compete with the piano tuner and laser light show tester just to name a few.


  1. Digimer says:

    Needs more cowbell. Err. Needs MOAR POWAR!

  2. sp00nix says:

    back in my day we would lick them wires to see if they were live. didnt need no fancy o-scopes.

  3. Rick says:

    Aside from destroying things in the most inefficient way possible, what are the applications of this thing?

  4. Ohh yes the good ol lick test. I still freak out my fiance when I take a random wallwart powersupply in my parts bin from a cellphone charger and “test” if its still good by licking the ends :)

  5. dcroy says:


    you can use such a setup to do capacitive discharge welding, really useful for welding battery cells together or bonding sheet metal

  6. Railgun!

  7. macw says:

    he’d probably have better results with the can-crushing if he built an actual coil rather than just halfassedly looping it around and holding it in place with what looks like duct tape.

  8. andrew says:

    Can you use one of these to create a small EMP? (like Ocean’s 11 or Golden-Eye style, but small)

  9. macw says:

    @andrew of course you can, that’s what is causing the cans to buckle inwards. If you put that coil next to a television and fired it you’d see all kinds of crazy distortion.

  10. Lt bob says:


  11. truthspew says:

    It’d also make a great power supply for a HERF weapon. You know, the HERF weaponry we’ll need to shoot down the SkyNet drones (X-47B anyone?)

  12. seanfalloy says:

    We built one at work to re-saturate Permanent magnets for motors. Ours is called the hammer of Thor and the switch is a brass hammer but it works great.

  13. seanfalloy says:

    Oh and we run ours at 900V But its not nearly as sophisticated as this one. Very nice work with the whole project

  14. strider_mt2k says:

    Man that was cool.

    Thank you for posting this.

  15. strider_mt2k says:

    Hey, could you do that thing they do with coins that makes ‘em smaller?

    -because those cans would be cool…you know…if they were, say, slightly smaller.

  16. joker says:

    this is the basis for all of Tesla work!

    the high voltage capacitor with spark discharge.

    for his :rail gun, free electron gun, world based communication and radiant energy system, and for the force field of course. just Great!

  17. joker says:

    that is not to mention his cosmic/solar ray collector and electric air plane, and a disc that can draw energy and be manipulated in the atmosphere with high voltage electro-magnetic forces… that God for the spark gap! ja ja ja

    this is just to name a few of his conclusions

  18. Mr. Name Required says:

    If I were him I’d be a trifle more safety conscious, like putting a whacking big DANGER label on his capacitor bank box to remind me every time I put my hands in it.
    And what’s with that annoying background music? It’d be nice to hear the guy talking without needing to resort to having that there, after all it’s interesting enough (for geeks) to not need it.

  19. Gilliam says:

    @strider_mt2k: fun size foods… are not fun! :(
    speaking of; i wnder how one of those half-cans would do against it.

  20. Coda says:

    Try with full unopened soda can please :D

  21. tron9000 says:

    I have one of those scopes at work. They can do alot, but when you try an export screen captures to a USB stick, if the drives bigger than 2GB, it doesn’t want to know.

    might have something to do with its based on Windows XP Embedded.

  22. IJ Dee-Vo says:


    Awesomness for one.

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