Jantzen P Core DCR weird measurement!

samuelj

Member
2017-05-23 8:11 pm
Hi,

I recently got some Jantzen 3.0 mH P-Core inductors rated at 0.19 Ohms DCR.

My LCR meter measures 0.5 Ohms while my DMM measures 0.2 Ohms!

Now, it is convenient to blame the LCR meter.
But when I measure an Air Core inductor rated at 0.7 Ohms DCR, both the LCR meter and DMM shows correct reading of 0.7Ohms.

Does anyone have an idea why these weird results?
Which one should I trust more? The LCR meter or the DMM?

If anyone has P-core inductors and an LCR meter, please measure once and share.
 
For low value resistances you need to use a four-terminal measurement (aka Kelvin connection), so that the resistance of the leads or connectors is not included in the measurement.

One set of leads passes a known current through the device (a bench power supply is a simple way to do this). Then use a multimeter in voltage mode to measure the drop across the device, R = V/I. Because no current passes through the multimeter leads their resistance doesn't affect the measurement.