## Phase Relation in Pure Inductive Circuit:

Phase Relation in Pure Inductive Circuit – As discussed already, the voltage current relation in the case of an inductor is given by Consider the function i(t) = Im sin ωt = I[ Imejωt ] or Im∠0° where

Vm = ωL Im = XLIm

ej90° = j = 1 ∠90°

If we draw the waveforms for both, voltage and current, as shown in Fig. 4.19, we can observe the phase difference between these two waveforms. As a result, in a pure inductor the voltage and current are out of phase. The current lags behind the voltage by 90° in a pure inductor as shown in Fig. 4.20. The impedance which is the ratio of exponential voltage to the corresponding current, is given by where

Vm = ωL Im where XL = ωL and is called the inductive reactance.

Hence, a pure inductor has an impedance whose value is ωL.

### Phase Relation in Pure Capacitor:

As discussed already, the relation between voltage and current is given by Consider the function i(t) = Im sin ωt = I[ Imejωt ] or Im∠0°  where

Vm = Im/ωC Hence, the impedance is Z = -j/ωC = -jXC

Where XC = 1/ωC and is called the capacitive reactance.

If we draw the waveform for both, voltage and current, as shown in Fig. 4.21, there is a phase difference between these two waveforms.. As a result, in a pure capacitor, the current leads the voltage by 90°. The impedance value of a pure capacitor