40kHZ ultrasonic transmitter circuit of five, by the time base circuit LM555 and the external components 40kHZ multivibrator circuit, the resistance adjusting resistor RP can c
hange the oscillation frequency. 3 feet from the LM555 output drives ultrasonic transducer T40-16, so as to emit ultrasonic signals. Circuit is simple and easy system. Circuit voltage of 9V, working current 40 ~ 50mA. Transmitting ultrasonic signals greater than 8m. LM555 NE555 direct replacement available, the effect is the same.