Parallel Resonance:

Resonance in a parallel R-C-L circuit will occur whenever the reactive current in the inductive branches is equivalent to the reactive current in the capacitive branches (or when X_L = X_C).  Since inductive and capacitive reactance currents are equal and opposite in phase and they cancel one another at parallel resonance.

Each with negligible resistance if a capacitor and an inductor, are connected in parallel and the frequency is adjusted like that reactances are exactly equal, current will flow within the inductor and the capacitor, other than the total current will be negligible.  A parallel C-L circuit will present almost infinite impedance. A capacitor will alternately charge and discharge by the inductor.  Therefore, in a parallel R-C-L, as in Figure, a net current flow by the circuit is at minimum since of the high impendence presented through X_L and X_C in parallel.