This switched regulator configuration was found in Motorola's 1969 documentation. The integrated circuit is from that time and is difficult to obtain today.
With an optical coupler and a power transistor, which can be the BD135, it is possible to control...
Used with old projector films, this circuit found in Signalite documentation from the 1980s,...
This filter that rejects determines frequency (notch) was found in a Popular Electronics of 1993....