This circuit was found in documentation from the 1980s. It is powered by the audio signal that must be cut. Transformers are the critical components and transistors are 2N2222.
LTC7841 PolyPhase® Synchronized Boost Controllers Mouser Announces Analog Devices LTC7841...
This interesting circuit is for controlling a small robot that searches for a light source. The...
This VCO or Voltage Controlled Oscillator was found in a Popular Electronics from 1991 but can be...