Power Rating

[Ansur]

Hi guys,

I have a Current Lover and Road Rage PCB on the way, which will be my first build where I'll actually have to gather all components myself.

Seeing as I only have a limited knowledge about the electronics, I'm a bit confused about the Power Rating of resistors.
From what I read, buying resistors with 1/4W should be OK for most applications.
With that in mind, I also gathered that RN55's are really great resistors, but they seem to come with 1/8W power rating.

So how do I determine how much I'll actually need for a given circuit?

[jkokura]

Generally, you don't need to worry about it in guitar pedals. I believe 1/4w resistors are very over-rated for what we use. You likely wouldn't have any issues with 1/16w resistors, but I've never seen nor heard of them being used. Don't worry about it, 1/8w or 1/4w are all fine.

As for how to figure it out... I think you'd look at the wattage of the circuit. I'm sure there's math involved, and I have not a clue what it is, but I'm sure someone around here does.

Jacob

[Ansur]

Has to do with Ohms law it seems. I seem to recall this from my Physics courses from way back

Thanks for the confirmation!

[stecykmi]

ohm's law and electrical power equation(s), P = V*I = R*I^2 = V^2/R

if you can find at least two of those variables, you can find the power dissipated by a resistor or circuit.

[TNblueshawk]

I would add that if you rock 1/8 resistors get your glasses out as they are tiny!