Heat dissipated by a resistor

[mrmecedes]

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What is the difference between these three formulas? I can't really get a conceptual grasp on these.

P = IV
P = V^2/R
P = I^2R

When should you use one over the other?

 

[Czarcasm]

What is the difference between these three formulas? I can't really get a conceptual grasp on these.

P = IV
P = V^2/R
P = I^2R

When should you use one over the other?

You can technically use any one of the three. You just have to be careful what value you're plugging in, particularly when considering the voltage you're using because you don't want to use the voltage of the battery, but rather the specific voltage drop for that resistor you're considering. Likewise, you want to use the actual current within the resistor and not the current passing through the circuit as a whole (the current flowing into and out of the resistor). For resistors in parallel, this current can split among the resistors and therefore, will differ in the amount of current passing into/out of a given resistor in parallel.

 

[mrmecedes]

That makes a ton of sense, thanks!