This circuit generates control signals for stepper motors. We found it in a 90s Popular Electronics. The power can be made with a 5 V supply so that it works as a shield.
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...