RE: [mowbot] [OT] Driving 6v DC motor with 12v power supply

Raymond Skarratt (skarratt nospam at
Wed, 19 May 1999 11:44:41 -0400

I think that just because the switching frequency happens to be out of the
audible range doesn't mean there isn't energy being wasted. It is probably
safe to say that switching at any frequency will waste a little energy.

Ray Skarratt.

-----Original Message-----
From: Dave Everett [SMTP:deverett nospam at]
Sent: Wednesday, May 19, 1999 6:19 AM
To: mowbot nospam at
Subject: Re: [mowbot] [OT] Driving 6v DC motor with 12v power

At 03:34 18-05-99 +0100, david steinke wrote:
>Whoa! Look at any speed controller for RC cars. They are typically
>switching frequency. Lower frequencies are worse, higher better.
The problem
>with higher frequencies is the lead inductance, transistor
switching times,
>and flyback damping. A good book is Bob Boucher's (??) Electric
>Handbook from Astroflight. It discusses at all this.

My only problem with audio is that if I can hear the motor switching
probably wasting energy somewhere. Do you have an ISBN for that book

Dave Everett

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