This circuit was found in American documentation from 1966, but it can be assembled with a modern equivalent transistor. The circuit is based on a mechanical tuning fork with a coil feedback system.
The output current of this circuit reaches 12 mA. The zener diode determines the output voltage. The...
Found in Maxim's documentation from the 90's, this circuit uses an integrated from the time...
Found in a 1980s documentation, this circuit makes use of components from that time. Modern...