Simplest PWM Motor Control Circuit Using Op Amp

Hello People!

This instructable is about how to build the simplest(probably) PWM circuit to control DC Motor speed, LED Strip Brightness, etc.

Specs:

Input Voltage : 5-30v

Current Handling : Depends on the MOSFET(Around 10A for IRFZ44)

Please comment if you tried building it!

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    8 Discussions

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    morton6689

    4 months ago

    i could be wrong but shouldn't there be a diode hooked across that motor to protect the MOSFET from back EMF? I realize this is a old post that i came across and doubt ill get a reply but if anyone new to electronics is going to build this i am 98% sure (i am not an expert on this) that you need to hook up a diode across the dc motor. look up snubber diode. when current is stopped the windings in in the motor have built up energy that becomes a voltage spike going backwards through the circuit which can damage (in this case) the MOSFET.

    1 reply
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    Usairum Mirzamorton6689

    Reply 3 months ago

    it depends upon which load you are using e.g if your load acts like a inductor (stores energy) then yes you need to have a protecting diode

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    megapix

    2 years ago

    Clever circuit. I also like the use of the bottle cap as a control knob.

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    BeachsideHank

    2 years ago

    What advantages does this circuit posses over the more popular 555 PWM designs?

    2 replies
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    Stuff BuilderBeachsideHank

    Reply 2 years ago

    Here are two

    One advantage might be higher operating voltage and other might be that two individual controllers can be designed using a single IC