Found in a 1966’s General Electric documentation, this circuit uses a triple diode from the time. The output current is 5 mA. It serves as a voltage reference.
IDT ZSSC3230 Capacitive Sensor Signal Conditioner Available from Mouser Electronics stock, this IDT...
We found this transmitter circuit for different frequency ranges in a 1992 documentation. The...
This crystal configuration can be made with triggers of any logic. The frequency is given by the...