A power controller monitors and controls supply of AC power to a load. A power supply derives DC power supply voltages from the input AC power. The power supply includes power dissipation circuit that dissipates excess power as a function of one of the supply voltages. A voltage sensing circuit provides a voltage sense signal that is a function of the voltage of the input AC power. A digital processor controls a switch that connects a load to the AC power based upon the voltage sensed signal.