
- If a sinusoid is applied to a resistor, power will be dissipated as heat.
P = V2 ÷ R for d.c. - The effective voltage (equivalent d.c.voltage)
for a sinusoid is called the rms voltage (root mean square)
This is voltage normally indicated by an a.c. voltmeter.
Vrms = 0.707 Vmax ; and Vmax = 1.414 Vrms - So P = Vrms2 ÷ R for a.c.