Introduction
Those of you modders, tinkerers, makers at one point or another would have encounter the need to have a finer control of DC motor speed, be it for robotic projects, RC, case mods etc. The simplest, no-brainer approach to that is by adjusting the voltage supply to the motor using a potentiometer. The higher the voltage, the higher the speed and vice versa.
Might be a good option for some cases, but the potentiometer approach doesn't perform too well when a much more stable and refined control is needed.