How to measure inductance and Q

[Helmholtz]

Three remarks:

1) The Q -factor of an inductor typically increases with frequency. It has little to do with the Q of the PU's resonance.

2) Calculating the theoretical Q from inductance, DCR and frequency doesn't make much sense as it gives no additional info.
An LCR meter can read Q values at say 100Hz and 1kHz. If the Q at 1kHz is lower than 10 times the Q at 100Hz, that indicates AC (Eddy current) losses, which increase effective series resistance.and lower L.

3) All typical LCR meters read apparent L rather than effective L.
If the measuring frequency is not much lower than the PU's unloaded resonant frequency (say by at least a factor of 5), the displayed L value will be too high.

[Mike Sulzer]

Three remarks:

1) The Q -factor of an inductor typically increases with frequency. It has little to do with the Q of the PU's resonance.

2) Calculating the theoretical Q from inductance, DCR and frequency doesn't make much sense as it gives no additional info.
An LCR meter can read Q values at say 100Hz and 1kHz. If the Q at 1kHz is lower than 10 times the Q at 100Hz, that indicates AC (Eddy current) losses, which increase effective series resistance.and lower L.

3) All typical LCR meters read apparent L rather than effective L.
If the measuring frequency is not much lower than the PU's unloaded resonant frequency (say by at least a factor of 5), the displayed L value will be too high.

Calculating the theoretical Q from inductance, DCR and frequency doesn't make much sense because that definition is not adequate for pickups with steel or even alnico cores, or with high conductivity covers or other shields. That simple definition of Q is standard in electronics because it is adequate for many practical inductors used in circuits.
This definition applies to resonances more generally (taken from here: https://www.electrical4u.com/quality...d-capacitor/):

It allows eddy currents to be included in the calculation; that is, the parallel as well as series loss can be included.