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Electronics => Electronics => Topic started by: Daanii on April 22, 2011, 07:42:28 PM

Title: Do I need a diode in my motor circuit?
Post by: Daanii on April 22, 2011, 07:42:28 PM

I've been seeing comments about the need for a diode in motor circuits. Do I need a diode when I'm hooking up a 12 Volt windshield wiper motor to a motor controller (the motor controller is this one:www.pololu.com/catalog/product/1373 (http://www.pololu.com/catalog/product/1373))?

For now,the motor is powered through a wall wart. Eventually, I will use a 12 Volt battery.

Title: Re: Do I need a diode in my motor circuit?
Post by: MikeK on April 22, 2011, 09:32:26 PM

No.  Protection diodes, or other protection circuitry, would be on the controller.  The connection diagram is on the page you listed.

Title: Re: Do I need a diode in my motor circuit?
Post by: Soeren on April 22, 2011, 09:37:51 PM

Hi,

Quote from: Daanii on April 22, 2011, 07:42:28 PM

I've been seeing comments about the need for a diode in motor circuits. Do I need a diode when I'm hooking up a 12 Volt windshield wiper motor to a motor controller (the motor controller is this one:www.pololu.com/catalog/product/1373 (http://www.pololu.com/catalog/product/1373))?

No, any commercial board should be protected and the manual doesn't say anything regarding such matters either, so they obviously don't expect you to put an external diode on it, but if in doubt, shoot them an email - after all, there's a lot of people that believe the L293D doesn't need external diodes.

If you have room for a diode, it won't hurt anything to use it of course, but it has to be a really fast diode to be really effective.

Title: Re: Do I need a diode in my motor circuit?
Post by: Daanii on April 23, 2011, 10:58:58 AM

Thanks, MikeK and Soeren. That's good to know.