I have a problem.... if you have a circuit with an inductor and resistor in series and a capacitor across them in paralell, with an AC source, is there a condition where the total impedance is a pure real number? I have got as far as getting the total impedance algebraically, but can't see where to go from here. I know that resonance in a series LCR circuit can cause this case to occur (when angular frequency=1/root LC), but i don't know if this works for paralell. Any help would be appreciated....