Now for a resistor: v = v

The power dissipated in a resistor is therefore:

Now for a capacitor: v = v

The power dissipated in a capacitor is therefore:

However the average value of sin (2wt) is zero and therefore the power dissipated in a purely capacitative circuit is also zero.

The same type of argument can be used to show that the power dissipated in a purely inductive circuit is also zero. For this reason capacitors and inductors are often used in a.c circuits to limit the current since they do not waste any energy.

A 220 W resistor is connected across an AC Voltage source where V = 150 x sin[2w60t]

What is the average power delivered to this circuit?

For an a.c signal the formula is:

V = V

Therefore: The peak power is given by:

Power = V

The ROOT MEAN SQUARE POWER is given by Power = V

Power= 150