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Project Notes

#046 MotorControlPWM

Tests PWM speed control of a DC motor.

Here’s a quick video of the circuit in action:

MotorControlPWM demo


Demonstrates using a PWM signal to control the current driving a DC motor, hence its speed.

The small PWM signal is amplied with an NPN transistor. An S9013 transistor is used in this case, primarily because:

  • it has relative high hfe(β); for class H it typically ranges 144-202
  • supports a decent continuous collector current (Ic) of 500mA (the motor I’m using is rated at 150mA)

A fly-back diode is placed across the motor to drain any voltage spike as the motor load is switched.


The Breadboard

The Schematic

Breadboard Build

Credits and references

About LEAP#46 MotorsArduino
Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is my personal collection of electronics projects, usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting (IMHO!).

The projects are usually inspired by things found wild on the net, or ideas from the sources such as:

Feel free to borrow liberally, and if you spot any issues do let me know. See the individual projects for credits where due. There are even now a few projects contributed by others - send your own over in a pull request if you would also like to add to this collection.