Stalefish Posted June 16, 2004 Report Share Posted June 16, 2004 I'm cooking up a new circuit and I realised that I've got a 2 pole switch, of which only 1 pole is being used.. Sooo, with the recent interest in LEDs, I was thinking of using the remaining pole as an on off switch for an LED.. That should make it function as an on/off indicator.. Question: Quite straight forward, really.. Can I just put an LED directly in series with the switch and a 9v battery or is a 9v too much? Also, do I need a resistor somewhere? Thanks!! Quote Link to comment Share on other sites More sharing options...
lovekraft Posted June 16, 2004 Report Share Posted June 16, 2004 Yes, you really need a series current limiting resistor to run an LED from a 9 volt battery - either check out one of the online calculators (here's one) and calculate for 15 mA or so, or just do what I do and use a 560 ohm for reds and yellows or a 390 ohm for blues and whites. Quote Link to comment Share on other sites More sharing options...
Stalefish Posted June 16, 2004 Author Report Share Posted June 16, 2004 Alriight!! Thanks, man!! Quote Link to comment Share on other sites More sharing options...
5thString Posted June 17, 2004 Report Share Posted June 17, 2004 Let me warn you, I don't understand a thing about electronics. This being said, last time I used a LED on a bass it was powered by two AAA batteries, that is 3V. So seen from here 9V seems fairly high... Quote Link to comment Share on other sites More sharing options...
Stalefish Posted June 18, 2004 Author Report Share Posted June 18, 2004 That's what the resistor is for.. It'll draw off a certain percentage of voltage depending on its resistance value so the voltage drop across the LED won't be so high.. I was just checking if the principle applied to LEDs as well.. I find 9v batteries more convenient.. Quote Link to comment Share on other sites More sharing options...
truerussian558 Posted June 18, 2004 Report Share Posted June 18, 2004 they last longer (imo) , and they look more convenient, plus you can shock your toungue if you want to Quote Link to comment Share on other sites More sharing options...
Stalefish Posted June 18, 2004 Author Report Share Posted June 18, 2004 Yeah.. Tongue shocking's always fun.. Quote Link to comment Share on other sites More sharing options...
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