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Subject: Re: LEDs For Dummies? Pointers needed.
Date: Mon, 9 Dec 2002 16:11:46 -0500
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Or you could use some diodes and resistors off the parallel port.
Dataline to diode to resistor (2k-5k?) to LED to ground? The more datalines
you have on the brighter it gets.
"Gregory L. Hansen" wrote in message
> In article ,
> Greg wrote:
> >I am starting a simple project where I would like to control an LED's
> >intensity from a computer. I have experience programming and with data
> >acquisition cards. However, I am a newbie with LED control.
> >Any pointers for good books or web sources for information on this topic
> >to get me started?
> More current makes the LED brighter, less makes it dimmer.
> What else could you need? You have the computer with the digital to
> analog converter. Connect the DAC output directly to the LED, with a
> resistor in series so that at the highest voltage, the maximum allowable
> current will be going through the LED. The LED itself will drop about 1.2
> volts. The LED is an approximately zero resistance load, so you'll burn
> it up if you try to run it without a resistor to limit the current.
> "A nice adaptation of conditions will make almost any hypothesis agree
> with the phenomena. This will please the imagination but does not advance
> our knowledge." -- J. Black, 1803.
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