May 3, 200422 yr Hi Guys, I could really use the help of anyone here who has experience with LED's. Lacking knowledge of electronics, I've researched enough where I feel comfortable experimenting with/blowing out some LED's. I'm at the point where I'm moving ahead with my main instrument panel and would like to begin working on some of the areas where backlighting will be needed. After reading though some information, I have a few questions. Can all the resistors be placed on a breadboard and then have wires running to the LED's where they will be located? If so, what are typical guages for the wire? Also, I understand the following equation "R = (12 - 3.4 - 3.4) / 0.020" 12 volts being the supply, 3.4 for the forward voltage........however "0.020amps"...and "We wish to pass 20mA (0.020Amps) through the LED. This is the part that confuses me. From where was the figure 0.020Amps acquired? Regards, Ricardo
May 3, 200422 yr Hi Ricardo,Twenty milliamps is a reasonable current to power an LED. Too much more than that and it begins to overheat. You may actually find that 20 is generating too much light, depending on the number of LEDs you use.As to where "20 ma" came from, it's just a typical current level for average LED usage. Specific LED models will have specific operating parameters defined in their spec sheets. It never hurts to check the manufacturer's rating, but somehow, 20 seems to (almost) always work quite well.Mikewww.mikesflightdeck.com
May 4, 200422 yr Hey, I found a whole bunch of useful stuff here on LEDs.I hope it helps! :)http://members.misty.com/don/ledx.htmlGood luck with your project!http://sky.wspilots.com/Logo/WSPilots.JPGwww.WSPilots.com
May 5, 200422 yr Don't blow any LED's!!!!First have a look at http://www.mikesflightdeck.com/led_dimmer.htmVery useful schematics...
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