Measuring Current in Inductor Circuit

[eev_carl]

Hi,

I'm measuring the current in an inductor circuit, but it doesn't match my calculated values.  I was wondering if someone could explain the discrepancy to me.  The circuit is 10 x 1uH inductors in series with an AC voltage source of 1.77V at 25KHz.  I calculated the reactance to be 1.57 ohms and the current to be 1.13 A (1.77 / 1.57).  However, when I measure the current with a DMM, I get 14.2uA.

This is a link to the inductors that I'm using: http://www.mouser.com/ds/2/390/RCH-654-523455.pdf.

Thanks,
Carl

[Benta]

Is your DMM able to measure anything at 25 kHz? BTW, I get 1.57 as well.

[eev_carl]

Hi,

Thanks for replying.  In the DMM manual, it lists a frequency range of 50 to 400Hz. My DMM is a Klein Tools MM700.

-Carl

[Benta]

A long way up to 25 kHz, then.

[Zero999]

Use an oscilloscope and sense resistor or current transformer. Note that the oscilloscope's chassis will be connected to mains earth and if your 25kHz signal source is to, the sense resistor idea may be a no goer: use a current transformer instead.