AC Voltage Measurement An ac voltmeter measurement indicates the amplitude of a sinusoid and not its phase angle. The magnitude and phase can be inferred by making several measurements and using KVL.

For example, Figure P8–79 shows a relay coil of unknown resistance and inductance. The following ac voltmeter readings are taken with the circuit operating in the sinusoidal steady state at f¼60 Hz: jVSj ¼ 24 V; jV1j ¼ 10 V; andjV2j ¼ 18V:

Find R and L:

Transcribed Image Text:

Vs + 200 www +V1- Relay coil + L V2 R FIGURE P8-79