Analog Discovery 2 - Impedance Analyzer & inductance measurements

[constantina]

Hello, I have trouble while trying to measure the inductance and impedance of certain coils . I place the coils, then when I run a single trial the value is not accurate and I can't understand if there is a problem with the settings in the waveform window or if my equipment is not accurate enough. Here is a screenshot of a measurement that we tried in the lab using a 150uH coil. is there anything wrong in the settings?

[attila]

Hi @constantina

Frequency is too high, close to resonant frequency. See at lower frequency and different reference resistor value if needed. Real circuits are not ideal.

 

[attila]

Hi @constantina

https://www.google.com/search?q=inductor+resonant+frequency
A coil is not an ideal inductor. It can be modeled with series resistance and parallel capacitance, or with additional components if you want to be more precise. As the frequency increases, the impedance of the inductor increases and the impedance of the capacitor decreases. The crossing point is the self resonant frequency. The inductance should be measured at lower frequencies, before this point. Like here 1mH with 1k reference around 100kHz, between 20k and 200kHz. If you want to measure it at lower frequency use lower reference resistor value.