#### guo-hai

##### Junior Member level 1

as I know the quality factor definition is energy stored/energy dissipated.

i found two formula to calculate it and got the same result

1. -Im(y11)/Re(y11)

2. Im(1/y11)/Re(1/y11)

Is there any relation between these two formulas?

and some other using impedance z to calculate it, is it just because series or parallel that matter ?

Thank You