Tres Bright 5mm LED's for Guitar Effects Pedal?

Leo_Loves Light

Newly Enlightened
Joined
Jun 21, 2009
Messages
1
Hi guys,

I know this is a forum dedicated to torches and whatnot but after a fair bit of googling, a lot of relevant threads were popping up here so I thought I'd ask y'all as there seems to be a lot of knowledge, wisdom and expertise here.

1) Could you tell me some examples of very bright 5mm LED's that would be fine to run off of the Volts / Amps inside a guitar effect pedal?

2) I've been advised to buy a couple of resistors ranging from circa 400ohm to 1.5Kohm to try out (to affect the brightness if it's too bright) - but I don't know whether to buy resistors rated at 1/4w or 1/2w or whatever.....?!

3) Where would be a good place in the UK to buy the above LED's + Resistors and wire to hook it up with? - there's a site called RapidOnline in the UK who seem fairly good although they only sell wire in rolls of like 10m and I only want a little bit...


thank you all very much in advance!
 

Biker Bear

Enlightened
Joined
Sep 9, 2006
Messages
279
Location
The Greater Los Angeles Metropolitan Sprawl
Are you looking for white LEDs, or colored ones?

LEDs have a characteristic known as "forward voltage" or Vf; to determine the resistor you need to limit the current through the LED, you use Ohm's Law. In this case, (Vsupply-Vf)/(Current in Amps)=(Resistance in Ohms). For example, if your pedal uses a 6v DC power supply and you have an LED with a 3.3 Vf that needs 40 milliamps: (6v-3.3v)/0.04A=67.5 ohms. If you want a lower drive current for less brightness - substitute that in the equation to get the appropriate resistance.

You likely won't find that exact value, but you likely can come close. As for wattage, Watts=Amps x Volts; in this case, 0.24w=0.04A x (6v-3.3v) - or about 1/10th of a watt, so 1/4 watt resistors would be fine.

Given that we don't know what brightness you want - you may have to experiment a bit. Note that different color LEDs have different forward voltages, so if you want a variety - you'll have to account for that.
 
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