How to measure AC current

Discussion in 'General Electronics Chat' started by jeffjohnvol, Nov 6, 2012.

  1. jeffjohnvol

    Thread Starter Member

    Oct 15, 2008
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    0
    I know there are devices like the Killawatt that already do this, but is there an easy low impedance circuit that can measure AC current going through a relay which produces a 0-5 volt DC signal for a micro controller to read?

    I'm trying to get an Arduino to measure when a laser cutter is running and the current to the main power supply turns on. I would like to replicate this on other devices as well, so making a sensor on the laser cutter wouldn't suffice. I don't expect I need to measure anything over 15 amps, and even just a on/off for high current loads would suffice.

    Thanks.
    Jeff
     
    Last edited: Nov 6, 2012
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,771
    971
    CT (current transducer)
    Looks like a donut (or a boxy donut)
     
  3. jeffjohnvol

    Thread Starter Member

    Oct 15, 2008
    27
    0
    Thanks! That pointed me to this, which I think I can use. Not "exactly" a CT, but it should do the trick. I just need a cap and a resistor to convert it to a DC signal.

    https://www.sparkfun.com/products/10341
     
  4. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
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