 Let's look at some example problems for electrical power in a resistor circuit. And the base equation we have for that is that the power is equal to the current times the voltage. Now, your professor and textbook might use just a V for voltage. In my class, they use the delta V to stand for voltage. As a simple example here, if you know the current and the voltage, maybe the current is 3 amps and the voltage is 5 volts, you just multiply those two numbers, which would give you 15 amp volts. But if you work through the units, and I do this in my introduction to this equation video, you'll see that that's really the same thing as 15 joules per second. And a joule per second is the same thing as a watt. So most of the time, the power is expressed in watts, although that's equivalent to a joule per second. And it is also equivalent to an amp times a volt. Now, you might have a situation, again, where you've got a metric prefix on one, or maybe even both of those. In this case, I've put in milliamps. Well, when you've got a milliamp times a volt, that's actually the same thing as a milliwatt. So you could just leave it in units of milliwatts. Or you could actually go through and put in the meaning of the metric prefix and multiply that out, in which case you would get the 0.015 watts. So just be careful with those metric prefixes and make sure you know what's going on with them so you can work through your equation. Now, we could also use this equation to solve for either the current or we could solve for the voltage. So these are just the algebraic rearrangements. And again, to solve for the current, we're just dividing through by the voltage. Or to solve for the voltage, we're dividing through by the current. So you could use either of those forms of the equations. Now, I'm going to go ahead and keep some of my same numbers here just as some example calculations so you can see how it works out. If I have 15 watts and 5 volts, that would give me my 3 amps. And if I was solving for the voltage, but I knew I had 15 watts and 3 amps, that would give me my 5 volts. So you can rearrange this equation to solve for the voltage or the current. Or you can use it in its original form to solve for the power. And again, this particular power is the electrical power being used in a resistor circuit.