I tried this thread in the Electrical Engineering area and nothing. So, hopefully someone reading this can explain this problem I am having.(adsbygoogle = window.adsbygoogle || []).push({});

We know that current in one direction is equal to its negative in the opposite direction. We also know P=IV for power. We also know that when current is going from + to -, P absorbed is +VI and P delivered = -VI. When you have current going from - to +, Pabs = -VI and Pdel = +VI.

So, you have -3A going from + to - through an element. There is 6V across that element. P=IV = (-3)(6) = -18W. Since the answer is - and current going from + to -, Pdel = -VI so it is -18W delivered. (Is my train of thought the correct way to view this?)

Now, imagine the same problem. You would have 3A going from - to +. So, P=IV=(3)(6) = 18W. Since current going from - to +, Pdel = +VI, so you have 18W delivered.

The signs are different! The book says the answer is P delivered = -18W. In both cases I found that the power is delivered. But the sign is off in the second example leading to an incorrect answer.....

Anyone know what the heck is going on?

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# Homework Help: Power (DEL or ABS)?

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