I was never taught electricity at school, nor was it a topic of dinner table conversation between my parents. But with reading, and having to change light bulbs or tune a radio, I have picked up a pretty sound working knowledge of electrical matters. It’s not comprehensive I know. I still can’t fully understand why you can’t boil an egg on an electric guitar or run a Basic program on a washing machine.

Most electricity is manufactured in power stations where it is fed into wires, which are then wound around large drums.

Some electricity however does not need to go along wires; that used in lightning for example. This kind of electricity is not generated, but just hangs about in the air, loose.

Electricity makes a low humming noise. This noise may be pitched at different levels for use in doorbells, telephones and electric organs.

Electricity has to be earthed, that is to say it has to be connected to the ground before it can function, except in the case of aircraft, which have separate arrangements.

Although electricity does not leak out of an empty power point, that power point is, nevertheless, live if you happen to shove your finger in it when the switch is on. If it is not leaking, what is it doing?

Electricity is made up of two ingredients, negative and positive. One travels along a wire covered in red plastic, and the other along a wire covered in black plastic. When these two wires meet together in what we call a plug, the different ingredients are mixed to form what we call electricity.

Electricity may be stored in batteries. Big batteries do not necessarily hold more electricity than small batteries. In big batteries electricity is just shoved in, whilst in small batteries (for transistors) it is packed flat.

A switch controls a small clamp or vice, which grips the wires very hard so that the electricity cannot get through. When the switch is flicked on, the wire is relaxed and the electricity travels to the light bulb where a bit of wire, called the element, is left bare. Here for the first time, we can actually see the electricity, in the form of a spark. This spark is enlarged many many times by the curved bulb, which is made of magnifying glass.

I have not touched on fuse wire. It has always amazed me that an industry which is so enterprising in most respects – the invention of colour electricity for use in traffic lights and the harnessing of negative electricity for refrigeration are two examples that come to mind – should still be manufacturing fuse wire too thin. By using chicken wire I now have a fuse box which – even when the spin-dryer burst into flames because of too much electricity having been fed to it – has for six months been as impregnable as the Bank of England.

In some respects, I know my knowledge is imperfect. I have not yet explored the field of neon signs – how do they make the electricity move about? And the pop-up toaster – how does it know when the toast is ready?

Logic would answer all these questions, but the light on my desk has just gone out.