The back EMF, along with the RL circuit in a brushed DC motor, brings non-linearity to the PWM control and the PWM frequency and PWM duty cycle become significant for getting the best output power.

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 ...

He hooks up the SN754410 to two motors, giving him speed and direction control for both based on the duty cycle of a PWM signal entering the chip for less than $2.50.

[youtube= [Spikenzie] has put together this nice kit for controlling a DC motor with RC servo signals. He’s using a PIC12F629 to convert the signal to PWM. As you can see in the video above,… ...