AC Current Clamp

Discussion in 'General Electronics Chat' started by JMJ, May 30, 2011.

  1. JMJ

    Thread Starter New Member

    Apr 14, 2011
    Now, the current clamp comprises of a split ferrite ring which a wire coil is wound in both halves forming the secondary winding like a transformer. If the "clamp" goes over the conductor and its able to measure the current proportionally.

    If the current clamp is used to read a magnitude of a sinusoidal current, it should be theoretically be used to inject current into a conductor? Right?
    Supposing, I use a frequency generator to provide signal to the coil, would conductor produce emf?

  2. Adjuster

    Well-Known Member

    Dec 26, 2010
    To some extent it would, but the voltage obtained would be quite small. These things operate with a considerable step-up ratio, so that a reasonable output voltage can be obtained into the high impedance of an instrument such as an oscilloscope, without needing to insert too much impedance in series with the line. Using the probe "backwards", you would be working against that ratio.
  3. someonesdad

    Senior Member

    Jul 7, 2009
    Theoretically, yes -- but as Adjuster says, the effect will probably be pretty small. Note that in the US, most ground fault interrupter circuits do exactly this with a 120 Hz current to be able to detect neutral to ground faults. You can open these things up and scavenge the 200 turn and 1000 turn current transformers to do this. The ferrite cores saturate pretty easily though (you can probably tell that I recently had some failed experiments with these things... :p).