SOLID-STATE RELAY

PURPOSE:To quicken the turn-off-timing of a MOSFET and to improve the switching speed by providing a bipolar transistor (TR) in response to an output of a photodetector TR. CONSTITUTION:When a DC voltage is applied between input terminals 1, 9 and a 2nd LED 10 is driven for stimulation in the state that a DC voltage is applied between input terminals 1 and 2 and a 1st LED 3 is driven for stimulation, an electromotive force generating element array 4 generates an electromotive force in response to the emitted input from the LED 3. When the light emitting Tr 11 is turned on in response to the light emitting input from the LED 10, a bipolar Tr 12 is turned off. As a result, a MOSFET 5 is turned on to close output terminals 6 and 7. When the LED 3 is non-stimulation drive state, a EET 5 is turned off to open the circuit connected between the terminals 6, 7. If on DC voltage is applied between the terminals 1, 9 even with a DC voltage between the terminals 1 and 2, since the Tr 11 is turned off and then the Tr 12 is turned on, the FET 5 is turned off and the circuit connected between the terminals 6, 7.