Hi there,
I'm creating an ultrasonic transmitter and reciever. I have created two different transmitters so far and have posted both circuit diagrams below. I am trying to transmit a constant 40kHz signal, but without a osc I can not be sure if both these astables are going low. At the moment I have a constant voltage from my multimeter on the output pin.
Please could someone tell me how to create a reciever, and if they believe these transmitter circuits will work?
Also, the slanted picture is from a datasheet, and the other is one I have devised and built.
Thanks for your help.