Using a circuit board

The diagram shows a very simple circuit board. The strips of aluminium foil do not follow the shortest path between the battery and bulb. Instead, they are set out neatly so that it is easy to see the path which carries the electric current. The foil is used instead of a wire (shown on the right).

When were circuit boards first used?
In 1947. Circuit boards in real pieces of electrical equipment contain lines of copper stuck to a board rather than the strips of aluminium shown in the model in the diagram above. This is because copper carries, or conducts electricity slightly better than aluminium. Copper also makes better contacts than aluminium.
They were first used in making radio sets. The components on a circuit board are joined to the copper strips by blobs of solder.


What does a circuit board look like?
This is a pocket calculator with its top removed. You can see the circuit board or printed circuit. The circular objects on the board are switches. Each one is linked to a button on the key pad of the calculator. The lines of copper link the switches.

Can circuits be made smaller than a circuit board?
Yes. These circuits are called integrated circuits, also known as silicon chips.
A very complicated circuit can be made on a thin sheet of silicon which is smaller than a postage stamp. The circuit and the sheet of silicon is known as a chip. Chips are used in many kinds of electrical equipment such as computers and calculators.


The remote control for a television has a key pad like a calculator. Does it have a printed circuit?
Yes it does. The circuit is connected to a component which sends an infra red beam to the television which lets you change the channel and the loudness of the sound.

When were chips or integrated circuits first made?
They were first made in 1959. Some of the first chips were used in equipment for exploring space. Later they were used to make home computers.