Can I run LEDs in a 12v-powered pedal?

[Bucksears]

I'm working on a 12V pedal, but was wondering if it's going to damage the on/off-channel LEDs by running those at 12V? Typically, my pedals have been powered by 9V and the LEDs are fine with those.

Thanks,

[a soBer Newt]

Check out http://www.muzique.com/schem/led.htm it will tell you the dropping R. you will need.

Nathan

[Mark Hammer]

Yup, the only concern is to make sure that the amount of current being fed to the LEDs is lowered when using a higher supply voltage.  That means raising the resistance value a bit.

Once upon a time, the resistor values recommended for the job were the ones you needed to use.  These dyas, however, the huge range of efficiency values of readily available LEDs means the LED you end up using might require only a fraction of the current that the circuit diagram suggests.   If it's a "garden variety" red LED from 20 years ago, 2k2 with a 9v supply might be spot on, but if you stick a superbright blue unit in, using even a 10k resistor with a 12v supply might conceivably blind you.  I made myself a little LED tester with a 12-position switch, battery snal, socket and nicely spaced resistor values ranging from 1k up to 18k.  To see what I need to use I turn it up to 18k, stick the LED in, connect the battery, and then turn down a step at a time, until I find a brightness that suits me.  I note the resistance value at that step, and either use that, or adjust upward or downward a bit to the nearest appropriate common value.

[HOTTUBES]

pretty Cool idea ...