Electrical Engineering ⇒ Topic : Resonance in A.C. Circuits

Resonance in A.C. Circuits

An a.c. circuit containing reactive elements (L and C) is said to be in resonance when the circuit power factor is unity.

Resonance means to be in step with. When applied voltage and circuit current in an a.c. circuit are in step with (i. e. phase angle is zero or pf. is unity), the circuit is said to be in electrical resonance. If this condition exists in a series a.c. circuit, it is called series resonance. On the other hand, if this condition exists in a parallel a.c. circuit, it is called parallel resonance. The frequency at which resonance occurs is called resonant frequency (f_r).