Motor Speed Control Cards

Instech’s motor control circuit cards regulate the speed of small DC permanent-magnet brush motors, such as those used in our miniature peristaltic pumps. Two cards covers a range of motors up to 24V at 0.2A.

These small boards are easy to integrate into a larger system; in the simplest configuration they require only an external potentiometer for speed control, a single power supply, and a motor.



  • Precise bi-directional speed control - Without a speed controller, your motor may slow significantly when a load is placed on it during operation (see chart below). With a speed controller, you set the motor speed with a control voltage, and it holds that speed constant over a wide range of torque. The speed control will also cause your motor to start predictably at low speeds.
  • Pseudo-tachometer feedback circuit - All of Instech’s control cards feature a fast feedback circuit which extracts the back EMF of the motor to regulate its speed. The circuit does not require a tachometer or encoder; it uses only two motor wires.
  • Active braking - Setting the control voltage to zero will cause the controller to drive the motor in the opposite direction, bringing it to a stop much faster than if the power were simply turned off. It will also actively prevent the motor from turning once it has stopped.
  • All analog design for low EMI.


Motor Speed Chart



Instech's motor control circuitry works only with permanent-magnet DC brush motors.


The prices below apply to quantites of 1-4 pieces. For pricing at higher quantities, please contact Instech.


U.S. Pricing

Model Name Price
MC50 Control card for PMDC motors, 50 mA $107 / each
MC200 Control card for PMDC motors, 200 mA $148 / each



PDF motor control cards information [PDF]