There are two kinds of materials: those that conduct electricity and those that do not. The ones that do not are called insulators. We use insulators to make sure that the electricity flowing through the conductors follows the paths we want it to. So, for example, the wires inside an electrical cable are all kept separate by enclosing each one on an insulating sheath made of plastic (an insulator).

We use a kind of plastic that is flexible for use with cables. We use another kind of plastic insulator for making circuit boards that go inside boxes of electronics. In this case we want the plastic to be an insulator and also to support the components that we want to use to make circuits with, things like chips and resistors.