Electronic circuit

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An electronic circuit is an interconnection of both active and passive electronic components, designed with the aim of arriving at a certain functionality. Though they are built on basic laws of electrical engineering, they exhibit highly complex behaviors.

Electronic components can be of two types ─ active and passive. Passive components are those components which never supply more energy than they absorb. This category includes resistors, capacitors and inductors. On the other hand, active components are those components which can supply more energy than they absorb. This category includes batteries, electric generators, vacuum tubes and transistors.

Contents

Some important electronic components

Transistors

These components are made from semiconductors. Semiconductors, typically silicon or germanium, are doped with impurities so that there can be a minority or majority of charge carriers, namely, electrons or electron-deficient regions called holes. Thus n-type or p-type semiconductors are arrived at, with 'p' denoting positive charge carriers and 'n' denoting negative charge carriers. The bipolar transistor, consisting of three layers of doped material, is widely used in electronic circuits. Other variants of transistors include the field effect transistor (FET), insulated gate bipolar transistor (IGBT) and metal-oxide semiconductor FET (MOSFET).

Integrated Circuits

Integrated circuits (IC) have transistors fabricated with photolithographic methods and enable the designer to create tens of thousands of transistors on a single chip. Minute conducting paths are present inside the IC to come up with highly complex special purpose circuits. IC chips are easy to manufacture and are cheap as well. These monolithic circuits have brought great versatility to electronic circuits.

Resistors

Resistors, which offer resistance to the flow of electric current, can come either as fixed resistors or variable resistors.

Capacitors

These consist of metal plates separated by an insulating layer in order to store electric charge. The effect of capacitance can be used in a number of ways, for example, to store data bits in a dynamic random access memory (DRAM) chip.

Inductors

Inductors consist of a conducting wire like that of copper that is wound in the form of a coil, in order to set up a magnetic field when a current is passed through it. It can be used to distinguish between rapid changes in voltage or current levels.

Transducers

These are devices that are used to convert a certain physical quantity into electrical signals such as that of current or voltage, and vice versa. An example of a transducer is the microphone, which converts sound signals into electrical signals.