What do you understand about Electronics?


Electrons are tiny particles that are parts of atoms. An electric current is a flow of electrons. Electronics is the study of how electrons behave and how they can be controlled so that they can do useful jobs. Nearly all the machines we use in our everyday lives – from radios, calculators and television remote controls to telephones, computers and cars – contain electronic circuits that make them work. Electronics are especially important in information technology and communications.

The study of electronics began at the end of the nineteenth century, and had its first practical use in the early 20th century in the development of radio communications. The first electronic devices were called thermionic valves. These included the diode valve, which allowed current to flow through it one way but not the other, and the triode, in which a small current could be used to control a much larger current. The parts of thermionic valves, some of which glowed red hot, had to be enclosed in a glass tube with the air removed to create a vacuum.

In the 1950s valves were quickly replaced by semiconductor devices. A semiconductor is a material that can act as both a good conductor of electricity and an insulator. Semiconductor devices are much simpler, smaller and more reliable than valves.

A thermionic triode valve was designed to amplify (strengthen) electric signals. A central electrode is heated inside a glass tube. Electrons flow from it to another, outer electrode. A small electric signal causes large changes to this electron flow, producing a more powerful electric signal.

There are dozens of different electronic components, but the most common ones are resistors, capacitors, diodes and transistors. A resistor restricts the flow of current in a circuit. Capacitors store electric charge. Current can flow into them until they are full, and out of them until they are empty. A diode allows current to flow one way but not the other. A transistor can act as a switch or an amplifier. It has three connections. The current flowing between two connections is controlled by a tiny current flowing into the third.

An electronic circuit is made up of components linked together by wires around which an electric current flows. By combining different components and connecting them in different ways, it is possible to make electronic circuits which do almost any job. In an electronic circuit, the components of the circuit itself control the current. For example, in a security light, the electric current is turned on or off by an electronic device that detects whether it is dark and whether anybody is moving nearby.

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