# What a resistor can handle

by WarrickF
Tags: handle, resistor
 P: 53 Hi Guys, Given a resistor, I understand how to use the bands to calculate the resistance, but how does one tell what the resistor is able to handle. For example, I have a 51ohm resistor that I connected to a DC power supply. At 5V all was fine, but when I increased the voltage to 10V the poor little resistor was glowing hot. The last band is for tolerance, but I'm not sure if this helps in any way to determine what kind of current the resistor can handle. Thanks Warrick
 PF Gold P: 7,120 The tolerance doesn't tell you how much power the resistor will take, it tells you within what range your resistor will actually perform at. For example, a 1000 ohm resistor with a 10% tolerance won't be manufactured to have 1200 ohms of resistance for example. When you purchased the resistor, it should say how much power it can handle safely.
 P: 53 mmm .... thanks. So what you're saying is that given a box of resistors there's no way of knowing?
PF Gold
P: 7,120
What a resistor can handle

 Quote by WarrickF mmm .... thanks. So what you're saying is that given a box of resistors there's no way of knowing?
Probably, but I don't know. Depending on what material they're made of, I bet a general power rating can be determined by people who know more about it than I do.
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