AVR-Chat

At 12:28 AM 7/20/2006 +0000, Ryan wrote:
>Alright, ideally, I could place a diode across the flyback source
>(solenoid)... but in this case I can't.  (The solenoid is connected
>remotely)  I can't figure out how to do this and provide reverse
>polarity protection.  If I place a polarity protection diode on the
>+12 input to the driver circuit, it will block any positive voltages
>I'm trying to "short" to +12.
>
>Does that make sense?  I'm still a little confused myself.  See
>circuit diagram here:
>
>http://i5.tinypic.com/20hjytt.jpg


D2 is your flyback/freewheeling diode.

Add a diode between Aout and your diode pair if you want some polarity 
protection on the load.

BTW Q2 is reversed, it will always conduct.

Robert


http://www.aeolusdevelopment.com/

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