This circuit appears on this site from different sources. This is from documentation from the 1980s. The operating system used is uncommon and can be replaced by a more modern equivalent.
We found this circuit in a 1975 publication. The circuit can be made with more modern equivalent...
August 2016 - It can be obtained from Mouser Electronics the power factor controller NCP1602 from...
This is a traditional circuit in which a 741 operational amplifier is used as an audio amplifier with...