We found this circuit in an old documentation. It can be elaborated based on modern components. The double transistor can be replaced by a matched pair.
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...