1/8 watt 4k7 resistor for LED?

[nag hammadi]

hey guys.  is it okay to use a 1/8 watt 4k7 resistor attached to the LED?

i ordered some by accident, and actually have a ton of them...

[R.G.]

P = I*V

That is, your resistor will burn up if it has to dissipate much more than 0.125W. At that power, it's surface temperature will be about 100C, the boiling point of water, if it's a normal resistor. It's life time will be relatively short, although perhaps long enough for stompbox use.

What is acceptable? For a 9V powered stompbox and a 1.8V LED, the V in the equation is 9-1.8 = 7.2V.  The current for a 4.7K resistor at 7.2V is I = 7.2V/4700 = 1.53ma.

The power is P = 7.2* .00153 = 0.011W, which is significantly less than 0.125W.

So yes, it will work.