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Subject: Re: LCD backlight Dimmer circuit
Date: Sat, 28 Sep 2002 10:09:24 +1000
X-Newsreader: Microsoft Outlook Express 6.00.2600.0000
"Richard Soennichsen" wrote in message
> That is a good idea. The circuit has a microcontroller with unused port
> pins. Maybe I will drive the backlight through a transistor all the time
> when the input is low. I have an timer interrupt every 1ms. I could
> the input and if high modulate the transistor to dim the backlight.
Fine if this is a 1-off for personal use. If it's a production design you
need to consider the EMC generated by 1kHz switching of 1-200mA/12V. The
things we could do with careless abandon some years ago are now mere fond
memories. (Just like being able to say 'gay abandon'!)
> "Sir Charles W. Shults III" wrote in message
> > Make a variable duty cycle oscillator (like with a 555 chip) and
> > output into a transistor. That transistor will drive the LED backlight.
> > the duty cycle will change the intensity.
> > Cheers!
> > Chip Shults
> > My robotics, space and CGI web page - http://home.cfl.rr.com/aichip
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