Translations of Encyclopedia about Physics

Electric appliances and equipment are rarely constructed to perform immediately after being plugged into an electrical socket. A simple example of some device which operates immediately in this manner are Christmas lights.

Most devices are designed for single, more or less complicated tasks or otherwise for multiple functions. For this reason, the operation of the device must be controlled, switched on or off, and regulated.

The most simple controlling device is the on/off switch. It is so common in fact that we do not even consider it a controlling element. The task of a switch is to turn a current on or off, or otherwise to reverse it.

According to some program, complicated controlling components are designed to change the intensity of a current. They may regulate various electrical circuits and, in a simple manner, may be programmable. An example of this is a program in an automatic washing machine which controls the opening and shutting of valves, the movement of the drum to the left or right, the pump, and so on.

There is often a differentiation between control and regulation. Control means that, according to some set schematic, the flow of current may change in different circuits (as in our automatic washing machine example). With regulation, quantities are measured and to which an appliance subsequently reacts. In a refrigerator, a compressor is activated or deactivated according to the internal temperature of the fridge.

Modern, complicated circuits are becoming increasingly smaller and are pressed onto plates. They are made from hundreds and thousands of individual components and are referred to as integrated circuits, ICS, chips or microchips. On an area smaller than 3 cm², highly integrated LSI (large scale integration) chips contain more information than 5,000 transistors.

This miniaturisation has enabled mankind to manufacture very small but affordable and powerful electronic devices.

For comparison, we only need to look at the size of the first computers. The old computers were able to handle medium to difficult, numerous tasks but took up many rooms due to their size.

Current can be switched with the help of transistors and other electrical components. With thousands of electronic components, there are an immeasurable number of options how to switch such components on or off. The language and logic of a computer is based on two states: 1- on, 0- off (0/1; yes/no, true/false).