PURPOSE: To reduce the number of cords used in connecting an ultrasonic sensor section with an ultrasonic control section by a construction wherein a power source for the amplification circuit of the ultrasonic sensor section is formed of a ultrasonic driving signal used to drive a ultrasonic vibrator.
CONSTITUTION: When output of a ultrasonic transmisssion signal generating circuit 9 in a ultrasonic control section 8 is low, transistors 17 and 16, 15 are respectively turned on and off. And a capacitor 5 in an ultrasonic sensor section 1 is charged with the source voltage applied between emitter and earth of the transistor 16, through a cord 20, diode 6, resistor 7, etc., so that the source voltage is supplied to an amplification circuit 4. Meanwhile, at the time of transmitting ultrasonic waves, the circuit 9 comes into the oscillated state and, when this driving signal assumes a low level, the capacitor 5 is charged to supply the circuit 4 with the source voltage similarly. Thus, a need of a power supply line is eliminated and the number of cords necessary for connecting the ultrasonic sensor section with the ultrasonic control section is reduced to three, resulting in a ultrasonic switch easy in connecting operation and simple in its construction.
IKEHARA TAKASHI
KURITA AKIRA
MIYAHARA TAKASHI
| JPS52152146A | 1977-12-17 |