Patent ID: 8193775

Claim:
A switch having a hysteresis characteristic comprising: a first voltage dividing resistor pair (R 1 , R 2 ) that divides the voltage of an external power source by the resistance ratio of the first voltage dividing resistor pair; a second voltage dividing resistor pair (R 3 , R 4 ) whose one end is connected to a positive electrode terminal of the external power source; a first switching device whose control terminal is connected to the junction of the voltage dividing resistors of the second voltage dividing resistor pair (R 3 , R 4 ), wherein a first electrode terminal of the first switching device is connected to the output terminal, and a second electrode terminal of the first switching device is connected to the positive electrode terminal; a second switching device whose control terminal is connected to the junction of the voltage dividing resistors of the first voltage dividing resistor pair (R 1 , R 2 ), wherein a first electrode terminal of the second switching device is connected to the other end of the second voltage dividing resistor pair (R 3 , R 4 ), and a second electrode terminal of the second switching device is connected to ground; and a resistor (R 5 ) that is connected to the junction between the first electrode terminal of the second switching device and the junction of the voltage dividing resistors of the first voltage dividing resistor pair (R 1 , R 2 ).