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 wireless infrared remote sound transmitter is from an article published in the August 1988...
High performance 16 A Buck regulators capable of operating at 2.7 to 4.8 V voltages and 0.25 to...
The circuit below was found in the March 1990 issue of Radio Electronics magazine. The circuit...