Found in a QST magazine from the 90s, this circuit broadcasts on different amateur radio bands depending on the coil. Data for the coil and crystal are provided next to the diagram.
Found in an American publication from 1968, this circuit aims to keep the torque of a DC motor...
This shield can be used both to interface microcontroller circuits or TTTL. The resistor in series...
Found in Popular Electronics this circuit uses current components to control a pump in order to...