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.
This circuit was found in an English magazine from 1976. The transistors can be the BC548. The...
This is an improvement on the previous circuit with a preamplification stage. The circuit is from...
We found this circuit in a 1974 integrated circuit manual. Operational amplifiers can be of...