Abstract: An electronic device according to the present invention includes a power supply unit and a load, the power supply unit including a ground terminal, a rectifier circuit, a circuit section connected to a DC output of the rectifier circuit, the circuit section supplying electric power to the load, a first varistor connected at one end thereof to one input end of the rectifier circuit, a second varistor connected at one end thereof to another input end of the rectifier circuit and connected at another end thereof to another end of the first varistor and an arrester connected at one end thereof to the another end of the second varistor and connected at another end thereof to the ground terminal, wherein an electrostatic capacity of each of the first and second varistors is 40% or more of a sum of earth capacitances of the power supply unit and the load.

Abstract: An input connection part having a first connection part and a second connection part, an anti-surge circuit having a first varistor and a second varistor which are connected in series so as to connect the first connection part and the second connection part, and a lightning arrester device connecting a connection point of the first varistor and the second varistor and a grounding connection part, and a power supply circuit connected to the anti-surge circuit are provided, wherein capacitances of the first varistor and the second varistor are any values from a value of 1.6 times a nominal capacitance of the first varistor and the second varistor to a value of 0.4 times the nominal capacitance.

Abstract: An electronic device according to the present invention includes a power supply unit and a load, the power supply unit including a ground terminal, a rectifier circuit, a circuit section connected to a DC output of the rectifier circuit, the circuit section supplying electric power to the load, a first varistor connected at one end thereof to one input end of the rectifier circuit, a second varistor connected at one end thereof to another input end of the rectifier circuit and connected at another end thereof to another end of the first varistor and an arrester connected at one end thereof to the another end of the second varistor and connected at another end thereof to the ground terminal, wherein an electrostatic capacity of each of the first and second varistors is 40% or more of a sum of earth capacitances of the power supply unit and the load.

Abstract: An input connection part having a first connection part and a second connection part, an anti-surge circuit having a first varistor and a second varistor which are connected in series so as to connect the first connection part and the second connection part, and a lightning arrester device connecting a connection point of the first varistor and the second varistor and a grounding connection part, and a power supply circuit connected to the anti-surge circuit are provided, wherein capacitances of the first varistor and the second varistor are any values from a value of 1.6 times a nominal capacitance of the first varistor and the second varistor to a value of 0.4 times the nominal capacitance.

Abstract: A power supply circuit drives circuits having different numbers of series-connected LEDs without changing a circuit constant or a component. An LED series circuit is connected to a power converter circuit of a power supply circuit. The power converter circuit is controlled by a control arithmetic circuit, and supplies a constant current to the LED series circuit. A voltage detection circuit detects a voltage applied to the LED series circuit. The control arithmetic circuit checks whether the LED series circuit has 40 LEDs or 20 LEDs, based on the voltage detected by the voltage detection circuit. The control arithmetic circuit holds a constant-current value table for 40 LEDs and a constant-current value table for 20 LEDs. In accordance with the detected voltage, the control arithmetic circuit selects one constant-current value table, and controls the power converter circuit based on the constant-current value table selected.

Abstract: A power supply circuit drives circuits having different numbers of series-connected LEDs without changing a circuit constant or a component. An LED series circuit is connected to a power converter circuit of a power supply circuit. The power converter circuit is controlled by a control arithmetic circuit, and supplies a constant current to the LED series circuit. A voltage detection circuit detects a voltage applied to the LED series circuit. The control arithmetic circuit checks whether the LED series circuit has 40 LEDs or 20 LEDs, based on the voltage detected by the voltage detection circuit. The control arithmetic circuit holds a constant-current value table for 40 LEDs and a constant-current value table for 20 LEDs. In accordance with the detected voltage, the control arithmetic circuit selects one constant-current value table, and controls the power converter circuit based on the constant-current value table selected.