Brushless DC Electric Motor (with Hall Sensor)




About: Music: my profession for over 40 years... Electronics: my beloved hobby always.

Intro: Brushless DC Electric Motor (with Hall Sensor)

This DCelectric motor project uses a Hall sensor to detect the position of the rotor and turn on the electromagnet in the precise moment.

Step 1: Overview of Device

Step 2: Circuit Diagram & Main Components

Sensor: UGN-3503-U hall sensor

IC1: LM358N (dual OP amp)

IC2: CD4001 (quad NOR gate )

FET1: IRFD120 (N-channel power mosfet)

This circuit is the same I used in my previous post "magnetic pendulum" . For additional details, refer to post.

Step 3: Hall Sensor

Step 4: Direction Detector

Step 5: 20mS Monostable ( Electromagnet ON Time )

Step 6: Output Mosfet Drives Electromagnet

Step 7: Electromagnet & Rotor Details.


1) electromagnet north pole UP

2) rotor north poles OUT

3) hall sensor branded side UP

Step 8: For More Details Watch Video. Thank You!



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    3 Discussions


    3 years ago on Introduction


    Can I suggest a reverse biased diode across the coil to stop back emf from damaging any of the other components.

    1 reply

    Reply 3 years ago on Introduction

    You´re right, a reverse diode on coil is generally recommended. I didn´t include one because IRFD120 (FET) breaks down over 100V, and has an internal avalanche diode protection across SD that will clamp short transients above that voltage. The rest of the components run no risk. Thank you!