So what's potential difference? Potential difference is what we use to generate current. It's like a reward for current. The bigger the potential difference, the more current will flow.
So potential difference is used to get us to make current do whatever we want it to do. It's a wonderful wonderful wonderful thing and it's used to drive essentially every circuit. So what is the nice source of potential difference? Well, batteries serve as a constant source of potential difference. When I have a battery that says one and a half volts on it, it means that the potential difference between the negative side and the positive side is one and a half volts. And always is one and a half volts. So if I connect that to a circuit, it will drive the current through the circuit and once the current gets to the other side, it just bumps it up to the top again because it's got to keep that same potential difference, one and a half volts.
So, they drive the circuits by forcing the current to flow and that's potential difference.