PURPOSE: To save the power consumption of a power supply device, by reducing a cathode current when a DC power is used for a TV picture receiver having a power supply device.

CONSTITUTION: A power supply stabilizing circuit 10 stabilizes a rectified and smoothed voltage and supply it to a load 3. At the same time, the circuit 10 connects the minus side power supply line to a luminance controlling variable resistor 6. A DC socket 2 is connected to the circuit 10, and a diode 12 is put into the area between the circuit 10 and a resistance 11. The resistance 11 is short-circuited by the contacts 2b and 2c, and the diode 12 conducts while an AC power supply is driven. At the same time, the voltage is supplied to the load 3 via the circuit 10. When a DC plug is put into the socket 2, the contacts 2a and 2b are connected to each other with the contacts 2b and 2c opened. As a result, the minus side of the resistor 6 is grounded via the resistance 11. Thus the cathode current decreases, and the current of a horizontal circuit is reduced. This can reduce greatly the power consumption of a power supply device.