Found in an English documentation, this circuit serves as a receiver for modulated sources of ultrasound. The sensor is a ceramic capsule. Transistors are general purpose types.
Found in an American documentation from 1968, this circuit senses the temperature through an...
In the figure we have an amplifier configuration found in an 80's documentation. The power supply is...
Found in an old publication, this is a transmitter with a spark coil. The high frequency...