This physical line servo control uses components that are not currently common. The circuit is from an 80's documentation and is powered by a voltage according to the servo.
Suggested by Amperex in 1968, this circuit is intended for hearing aids. The integrated circuit...
This circuit was found in a Popular Electronics from April 1993. It is a voltage regulator circuit...
This simple unregulated power supply with half-wave rectification is for small appliances that do...