Members fragglerick Posted March 28, 2006 Members Share Posted March 28, 2006 It seems that in most cases with a 9V power supply a 4.7k resistor is used. What value would I use if I wanted to make the LED brighter without heating it up too much or burning it out? Link to comment Share on other sites More sharing options...
Members Kimsuzzie... Posted March 28, 2006 Members Share Posted March 28, 2006 1k Link to comment Share on other sites More sharing options...
Moderators AMZ-FX Posted March 28, 2006 Moderators Share Posted March 28, 2006 A safe way is to put another 4.7k in parallel with the one already there.... just solder it on the existing one. -Jack Link to comment Share on other sites More sharing options...
Members fragglerick Posted March 28, 2006 Author Members Share Posted March 28, 2006 Originally posted by AMZ-FX A safe way is to put another 4.7k in parallel with the one already there.... just solder it on the existing one.-Jack Won't that double the resistance and make it dimmer? Link to comment Share on other sites More sharing options...
Members varialbender Posted March 28, 2006 Members Share Posted March 28, 2006 In parallel, it'll cut the resistance in half. Link to comment Share on other sites More sharing options...
Members fragglerick Posted March 28, 2006 Author Members Share Posted March 28, 2006 Originally posted by varialbender In parallel, it'll cut the resistance in half. Cool, and that's safer than a 1k? Link to comment Share on other sites More sharing options...
Members varialbender Posted March 28, 2006 Members Share Posted March 28, 2006 PS the formula for resistance in parallel: Requivalent = 1 / (1/R1 + 1/R2) If there are 3 resistors: Requivalent = 1 / (1/R1 + 1/R2 + 1/R3)Etc... Link to comment Share on other sites More sharing options...
Members varialbender Posted March 28, 2006 Members Share Posted March 28, 2006 Originally posted by fragglerick Cool, and that's safer than a 1k? Well, the less resistance, the brighter, but you don't want too little resistance, or it'll burn out the LED.Two 4.7k resistors in parallel are the same as one 2.35k resistor, which is more than 1k, so it's further away from burning the LED than the 1k is. If you're mod'ing something, then it's easier to add a resistor in parallel than it is to remove a resistor and replace it. Link to comment Share on other sites More sharing options...
Members Marcus Dahl Posted March 29, 2006 Members Share Posted March 29, 2006 Originally posted by fragglerick Won't that double the resistance and make it dimmer? You're thinking of a capacitor. Parrellresisitor cut's in halfcapacitor doubles Seriesresistor doublescapacitor cuts in half In esence he can just use a 2.2K resistor. Link to comment Share on other sites More sharing options...
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