Question

Why parallel resonance is termed as rejector circuit?

Answer 1

As a parallel resonance circuit only functions on resonant frequency, this type of circuit is also known as an Rejecter Circuit because at resonance, the impedance of the circuit is at its maximum thereby suppressing or rejecting the current whose frequency is equal to its resonant frequency.

Answer 2

Because at resonance frequency in LRC parallel circuit,impedance is high.

Explanation:

A parallel resonant circuit has at its heart an inductor and a capacitor. These are the two parallel components. They each react to voltage and current 180 degrees out of phase with each other. When we "hit" this circuit, called a parallel tank circuit, or just a tank, with voltage, one component is "putting energy into the circuit" while the other one is "storing it up" and then the two components switch roles. The result is that the tank will oscillate, and the frequency of oscillation will be determined by the value of the capacitor and the inductor.

Because at resonance frequency in LCR parallel circuit,impedance is high,

So it minimize the current. thus we say its a rejector circuit .