Electric device

An electric device comprising:

• a control microcomputer;
• a power supply circuit for converting a power supplied from a commercial power supply to an operating power, and for outputting the operating power;
• and
• a power stoppage detection circuit for inputting a signal generated according to an output of the power supply circuit to a power stoppage detection terminal of the control microcomputer, wherein
• the control microcomputer detects the power stoppage occurs to the power supply circuit based on the signal input to the power stoppage detection terminal, and controls the electric device to stop an operation of the electric device based on detection of power stoppage,
• in a stand-by mode in which the electric device fails to operate and the power is supplied to the electric device from the commercial power supply, the power supply circuit performs an intermittent oscillation with one cycle that consists of a period, in which a power semiconductor switching element oscillates and the power is output, and a period, in which the power semiconductor switching element does not perform the intermittent oscillation and the power is not output, and
• if it is not detected that the signal is continuously input to the power stoppage detection terminal for a constant time or more relative to the one cycle of the intermittent oscillation, the control microcomputer detects that the power stoppage occurs to the power supply circuit.