“HW-687 is one easy module for adding speed regulation to your next DC motor-based project. It is a simple pulse-width–modulated speed controller providing smooth control with almost no jerks. There ...
En route to getting the off-the-peg DC-51 motor speed controller to better suit my small milling machine, I had a go at working out what the circuit is. Approx circuit of DC-51 motor speed controller ...