Current Clamp Meter Accuracy

Discussion in 'General Electronics Chat' started by chevylu, Sep 8, 2008.

  1. chevylu

    Thread Starter New Member

    Aug 15, 2008
    Is anyone familiar with the Current Clamp Meter kit available at

    The kit appears to follow this article:

    My multimeter has 5 DC Voltage ranges as follows:
    400mV.....100 microvolts

    Do you think the kit would be able to provide accurate readings down to about 25 milliamps? I would like to use it to measure the parasitic battery drain on my car without having to insert the ammeter in line with a battery cable.
  2. SgtWookie


    Jul 17, 2007
    Not with the meter you have. 100uV = 0.1mV, and 0.1mV = 100mA current. You would need four times the resolution on your meter to be able to measure in increments of 25mA.

    A 90mA constant drain on your vehicle's battery will likely result in discharging the battery sufficiently over a few weeks' time to discharge it enough so that you won't be able to start it without a jump, or recharging the battery.

    It's hazardous to your meter attempting to measure current on a motor vehicle, an un-planned for sudden load (such as opening a door, a remote being activated, etc.) will at least blow the fuse.

    Consider purchasing a 1 Ohm power resistor, and install it temporarily (for troubleshooting purposes) between the battery + terminal and the + lead. Since I=E/R, measuring the voltage drop across the 1 Ohm resistor will allow you to directly read the current being used by your vehicle. 1mV=1mA. Not as convenient as a clamp-on ammeter, but certainly less expensive.

    As far as the clamp-on meter goes, I suppose it's output could be amplified - but I'm not going to pay for a subscription to for the privelidge of reading the article.