I'm having a hard time understanding why one couldn't measure the inductance of a coil using a simple multimeter capable of measuring AC voltages and currents:
The total series impedance could be expressed as:
EDIT: given the 90 degrees phase difference, the correct formula is:
Now, if I'm not mistaking, the same impedance can be expressed as the ratio between the measured effective AC voltage and current,
I (as complex values):
We can then obtain
EDIT: the correct formula is:
In conclusion, by measuring the AC voltage, current, coil DC resistance and by choosing a well known external resistor, we could find out the coil inductance.
Am I mistaking? If yes, where? If no, why all google searches for "measuring inductance" present more complex methods involving function generators, oscilloscopes and phase-shifting?