When building a circuit with a battery, it's important to note that a battery is a collection of a number of cells. Learn about how a higher voltage battery will create a brighter bulb in a flashlight with help from a science teacher in this free video on circuits and batteries.
Hi, I'm Steve Jones and I'm going to show you how to build a circuit with a battery. Now this is not with a cell. A cell is a single object, whereas a battery is a collection of cells, a number of cells. And this is what makes it distinctive. It's very important to be able to change the voltage that we have in a circuit to drive different components. And very often we want higher voltages. For example, in a car we have six cells in a battery to give us twelve volts. We cannot have a single cell which gives us more than two volts. And the lead acid cell that we use in a car is a two volt cell, so six of those gives us twelve volts. So, how does this work? Well, if I put a series of cells together, positive to negative, I've shown here, so this is plus minus, plus minus, then here I've got two cells. Each is 1.5 volts. Overall I will get three volts. And you will think 'Well, why would you want to do anything other than that? If you want six volts, then you'd put four cells, if you want twelve volts, you would put eight cells and so on.' Well sometimes you want a higher current capacity. You want more current in the circuit. The object you're using takes more current, more power, and therefore, very often whilst it's voltage might be the same, you actually need more current. And the only of doing in that is to connect the two cells in parallel. This is also a battery. So this is a battery, but it has a higher current capacity. In fact, this is a 1.5 volt battery. We could always, of course, put another cell in here and one in here, and we could increase that, therefore, to create a three volt battery with a higher current capacity. So by putting the various cells together in parallel or in series, we can increase the voltage, and we can increase the current capacity. In a circuit of this kind, here we've got a three volt bulb. It would be no good putting a l.5 volt cell in that, so we need, automatically, two cells, each of 1.5 volts to drive a three volt lamp. In your common torch, you usually have two cells or three cells. If you got three cells, that's going to be 4.5 volts, and when you look at your bulb rating in your torch, you should find it's 4.5 volts. Two cells, it'll be a three volt rating on the bulb. Obviously the higher the voltage and the higher the current capacity, the brighter the bulb, the brighter the torch. So that is, basically, how to build a circuit using a battery.