 Now we look at parallel capacitors. And we start again looking at a basic capacitor circuit, which has one battery and one capacitor. Our simple equation for the capacitance relates the charge to the voltage across the capacitor. And we can algebraically rearrange this equation to solve for either the voltage or the charge. So now we get to a parallel circuit. And the key point in a parallel circuit is that there are two or more paths around the circuit. In this case, one of the paths goes through capacitor one, and one of the paths goes through capacitor two. Now the other way to think of this is to look at the fact that it splits. So I've got current coming into this one point, and then the path splits into two other paths. But later on, it comes back together. So we end up having current or charge or a path which splits and comes back together. And that's our parallel circuit. So now let's think about the charges. Now remember, the battery is going to move charge from one side of the capacitor to the other. And you'll notice that charge one was on capacitor one, and charge two was on capacitor two. And they don't have to be the same amount this time. Just to look at that again, each one is moved. But notice that they both went through the battery at the same time. So that means I end up with an equivalent capacitance being moved through the whole circuit, which is charge one plus charge two. Now let's look at the voltages. So the battery is going to set up a potential difference, which is what the voltage is. So I've got a high potential on the positive side of the battery. And because both capacitors are connected to that high side of the battery, they both have a high potential on them as well. And the low side of the battery is also going to create a low potential on both. And this is the same low potential on the bottoms of all the capacitors and the same high potential on the tops of all the capacitors. So my capacitor one is going to have a voltage which is the potential difference of high minus low. And capacitor two is also going to have a potential difference of the high minus the low. So in parallel, the voltages, whether it be the equivalent voltage of the battery, capacitor one or capacitor two, are all going to be equal voltages. So now we can look at the capacitance in parallel. And we're going to start by using our previous equations. I'm going to start with the charge equation here and remind myself from those initial equations that the charge on one and the charge on two could be written out in terms of the combination of the capacitance and the voltage. And the same is true of the equivalent. So I can use this capacitance times voltage to rewrite my equation for the charges adding up. But I also recognize that the voltages are all the same. So I could divide and cancel that out, leaving me with just my equivalent capacitance is equal to C1 plus C2. So in summary, for a parallel set of capacitors, the charges add up, the voltages are the same, and the capacitance adds up. What if I had three or more capacitors in a parallel circuit? Well, in a parallel circuit, then my charges are still going to add up, but now I add up all three. My voltages are still going to be the same no matter how many voltages I have. And my equivalent capacitance is going to add up all the individual capacitance. So that's your parallel capacitors.