The phase shift of the circuit in Figure 18-3, at the critical frequency is:
A) -90°
B) 0°
C) 60.254°
D) -45°

Question

Quizplus · Accepted Answer

At the critical frequency of an RC (resistor-capacitor) or RL (resistor-inductor) circuit, the phase shift is -45°. This is because, at the critical frequency, the reactance of the capacitor or inductor equals the resistance, leading to a phase difference of 45° between the voltage across the resistor and the total voltage, but since the voltage across the reactive component (capacitor or inductor) leads (in the case of the capacitor) or lags (in the case of the inductor) the resistor voltage by 90°, the net phase shift between the input and output is -45°.

The Phase Shift of the Circuit in Figure 18-3, at the Critical