We found this circuit in an American documentation from 1969. The circuit works with the polarized transistor in reverse in the avalanche mode.
This circuit, found in documentation from the 1980s, uses an operational amplifier from that time....
This low frequency sinusoidal oscillator was obtained in documentation from the 1970s. Operational...
This circuit was found in a 1980s documentation. It is intended for remote vibration monitoring...