Quality Factor of Parallel RLC Circuit:

Consider the Quality Factor of Parallel RLC Circuit shown in Fig. 8.16.

Quality Factor of Parallel RLC Circuit

In the circuit shown, the condition for resonance occurs when the susceptance part is zero.

Admittance

The frequency at which resonance occurs is

Quality Factor of Parallel RLC Circuit

The voltage and current variation with frequency is shown in Fig. 8.17. At resonant frequency, the current is minimum.

Quality Factor of Parallel RLC Circuit

The bandwidth,

For Parallel RLC Circuit, to obtain the lower half power frequency,

From Eq. 8.26, we have

If we simplify Eq. 8.27, we get

Quality Factor of Parallel RLC Circuit

Similarly, to obtain the upper half power frequency

From Eq. 8.29, we have

Bandwidth

The quality factor is defined as

In other words,

Quality Factor of Parallel RLC Circuit

In the case of an inductor,

The maximum energy stored = 1/2 LI2

Energy dissipated per cycle = (I/√2)2 x R x T

The quality factor

For the capacitor, maximum energy stored = 1/2 (CV2)

Quality Factor of Parallel RLC Circuit

The quality factor

Quality Factor of Parallel RLC Circuit