A parallel LC circuit is in resonance when a current detected through the parallel circuit falls in phase with the supply voltage, according to Electronic-Tutorials. At the point of resonance, a large circulating current can be detected between the inductor and the capacitor because of energy stemming from the oscillations. A parallel resonant circuit holds energy in the inductor’s magnetic field and the capacitor’s electric field.
A simple parallel resonance or tank circuit experiences resonance when the capacitor’s and inductor’s reactance equal each other. Inductive reactance surges with increase in frequency while capacitive reactance decreases with surging frequency, meaning that the two reactances can equal each other at only one point in an oscillation. When the capacitive reactance matches the inductive reactance at the point of resonance in a parallel LC circuit, the circuit’s sum impedance soars to infinity, meaning that no current is drawn from the AC supply.
According to Value Amrita, the behavior of a parallel LC circuit is utilized in devices such as oscillators, graphics tablets, tuners, mixers, electronic article surveillance and contactless cards. Such a circuit shares some characteristics with a series resonance circuit, with the formula for calculating the resonant frequency being the same in both types of circuits.