The circuit is a PCB drill speed controller, which can be used to control the speed of any 12VDC small pcb drilling units. Inexpensive and useful circuit for electronics hobbyists.

This DC servo motor controller can also be used with an external potentiometer or the integrated on board potentiometer. For applications with existing PWM signals available this can also be used ...

His talk at the 2018 Hackaday Superconference covers how he built a brushless DC motor and speed controller into a PCB. You can watch the newly published video after the break.

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.

It is a Clarke DCM10, a variant of Sieg’s X1, sometimes knows as a ‘micro mill’. Mine has a ~230V 150W brushed dc motor that needs driving from 240Vac mains power. Almost randomly, I settled on a ...