The circuit shown in the figure below is from the 1993 Linear Technology Applications. The operational ones used are uncommon and the use of equivalents can be analyzed.
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...