What is the signifance of parallel/series inductance/capacitance measurements on RLC meter?

Question

The RLC meter I use includes these measurements: serial inductance, parallel inductance, serial capacitance, and parallel capacitance.

What are their differences, and how are they important respectively? I think serial inductance just means the usual inductance shown on an inductor datasheet.

Also, on the meter there are serial resistance and parallel resistance measurements. If I put a coil between the probes, serial resistance just gives me the wire DC resistance, but what would be the significance of the parallel resistance?

Answer 1

Serial r-l or parallel R-L are "equivalent" circuits of the same "device" drawn at ONE frequency.
It is usually simpler to use serial representation, but sometimes it could be easy to use the other.
There are relations for calculating one knowing the other.
It involves for inductors, with some assumptions, the factor Q = w*l/r ...
Formulas general case. For capacitors, it involves the D factor.

A Maple sheet is used to check that, when Qs > 10 (black line),
formulas can be simplified (Lp = ~ Ls, Rp = ~ rs*Qs^2 ).