 Now we're ready to take a look at parallel circuits and how you would solve for all the values for that circuit. Now, if you haven't watched the general strategy for solving these equations, that video, you probably want to go back and watch that video. But we're using the same strategy here as we did in series. And that's by keeping all of our material organized in a table. Each row is still governed by the Ohm's Law equation, but now each column must follow the rules for a parallel circuit. And let's take a look at a really simple circuit here in parallel. And in this case, I'm giving you as knowns the initial resistor values and the voltage of the battery. And in a simple parallel circuit, the voltage of the battery is the equivalent voltage over the parallel combination. Now in this case, we have to start with our resistor column because you need to have information here. And you could figure out the equivalent resistance. But actually, there's something else you can do here just to show you how this works. Because in parallel, all the voltages are equal. And that means all three values in the voltage column have to be exactly the same. And so that means you already know that the voltage on both resistor one and resistor two have to be that nine volts. And once you know that, you actually have some options for how to move forward. I'm going to go ahead and tackle this the way that we traditionally do, which is to find that equivalent resistance first. Now when you're finding that equivalent resistance, you'd have the one over, and don't forget to use your out of parentheses here, one over four Ohms plus one over two Ohms. When you put that into your calculator, you're going to get a value like 1.333 Ohms. Now, here's a point I want you to be careful of because when you do this calculation, your calculator might tell you something like 1 point repeating three. And if you just use 1.3, you're going to end up with some errors at the end of your calculation, where things are just not quite going to work properly. So you need to make sure that you're actually using as many significant digits as you can. Now at this point, I can find my current values and each one of the currents has to be the voltage divided by the resistance. And in this case, that would be nine volts divided by four Ohms, which would give me 2.25 amps. And if I've got this value here, that's going to be nine volts divided by two Ohms, which is going to give me 4.5 amps. And according to the parallel circuit rules, if I add those two values up, I should get 6.75 amps. Now, here's where that rounding is really, really important. If I've got 1.33 Ohms times my 6.75 amps, I do actually get the nine volts. If I had rounded this off at just 1.3, it wouldn't quite work out properly. And I'd end up having some rounding errors in there. So if you keep it out to larger decimal places, you're going to get more accurate values on that calculation. Now you still need to practice by plugging these things into these equations to make sure that you understand when you're solving for those currents, it was the voltage over the resistance and making sure you get the same values I do. And where you're adding things up, whether equal or where you're using that inverse rule. I've got one more quick example to show you, just to give you another clue for how you might tackle some of these problems. And in this particular case, it's still being a parallel circuit that would be given in the word problem or the diagram, but you're given different pieces of known information. This would be a very unusual problem, but I want to show you that you can still do it. And in this case, your first clue, once you put it into the table format, is realized that you know all but one of the currents. And those values for the currents, whatever's here and here, have to add up to be eight. So what would you need to add to six to get eight? Well, that would be 2.0 amps. Once you know that, you can find the voltage on the top row, because it's going to be the current times the resistance. 2 amps times 5 volts is going to give you 10 volts. 2 amps times 5 ohms gives you 10 volts. And once you know one of the voltages, all of the voltages have to be the same for a parallel circuit. And remember, these rules are only for a parallel circuit. When we had a serious circuit, it was the currents that all had to be the same. Once you do that, again, now we've got columns or rows, I should say, where there's only one thing we don't know. And so you would come back to this form of the equation, where it's going to be your voltage over your current. And so our voltage divided by our current and our voltage divided by our current, we could figure out the values here. And again, you want to make sure that you're using at least three significant digits on each one of these. And then putting in our values and our units. Now, I went through this one very quickly. Make sure that you go back and double check, and you can watch the video if you need to go back and see where we're at. But each row has to follow the row columns from Ohm's law. And each column has to follow the parallel column once. And that's because I said at the very beginning that this was given as a parallel circuit.