Electric control circuit for safety apparatus in automotive vehicles

摘要

In an electric control circuit for a safety apparatus including an actuator in series with an electric power source through a normally open switch to be electrically operated upon closure of the switch in the occurrence of a vehicle collision, a resistor is connected in parallel with the switch and has a predetermined resistance value defining an electric current applied to the actuator through the resistor to maintain the actuator inoperative. The control circuit further comprises a differential amplifier for amplifying a terminal voltage appearing between the opposite ends of the actuator to generate an amplified voltage therefrom, a constant voltage generator for generating a constant voltage therefrom, a comparator for comparing the amplified voltage with the constant voltage to generate an output signal therefrom when the amplified voltage becomes lower or higher than the constant voltage, and an indicator for informing of malfunction of the control circuit in response to the output signal from the comparator.