This circuit is from the Motorola Linear Databook of 1990 and can be implemented with other operational amplifiers. The power supply must be symmetrical.
The transformer inf this circuit is a 6 or 9 V unit and diodes 1N4002. The filter capacitor is 2...
This circuit has been found in an old American documentation and is intended for calibration of radio...
With this circuit, from a 1991 publication, it is possible to regulate the output of a symmetric source...