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# What is a 1/4 watt resistor? Answered

Alright, So I know the basics about resistors and what-not, but as I was buying beginner supplies, I noticed there were resistors in OHMs and Watts, What's the difference between the two? And like, can the unit Watt be transfered into OHMs? And which one would I use when my general area of working would be around basic LED work and noob stuff like that xD?

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## 5 Replies

The power rating of the resistor is stated in Watts. In other words, after you have designed your circuit, you look at the selected resistors, and you calculate the power dissipated (I) Power = current x voltage (P=V/R, or P= V2 /R or P= I2 x R- you MUST select resistors with a power rating that exceeds the result.

So you don't work between Ohms and Watts, you work withBOTH in a successful, fire free, design.

led235 (author)2009-07-26

simply, it takes 9 volts down to 3 volts

nsrinivas1 (author)2013-10-24

one point i just want to add, to above explanation.generally LED drive current in the order of 2mA to 5mA.So we have to select a Resister based on this using KCL.