Electronic component

From ArticleWorld

Electronic circuits comprise of interconnected electronic components. Electronic components are thus the functional blocks of any electronic system. Leads are provided on the discrete components and connected with one another on a printed circuit board by soldering. The interconnection is decided according to the desired function of the electronic product. There are two main ways of classifying electronic components. In the first way, classification can be done on the basis of packages provided. They can be packaged separately as in resistors, capacitors, transistors and diodes. They could also be in the form of complex groups such as integrated circuits.

Components can be classed as passive if they require an outside source of energy, and as active if they can produce their own energy for operation.

There are several electronic components available in the industry.


Passive components

The components that do not produce their own energy for operation, like fuses, capacitors, inductors, resistors, switches and transformers come under this category.

  • Fuses are used for the purpose of protection of the more delicate parts of any electronic circuit. They are rated in milli-amperes.
  • Capacitors are used for the purpose of storing charge. They consist of two metal plates that are separated by an insulating material known as a dielectric. If a potential is applied on the two plates by means of a source, an electric charge will flow through the plates till there is enough accumulated charge in the plates that it begins to behave as an “open circuit”.
  • Inductors consist of a coiled conducting wire meant to produce a magnetic field around it when a current is passed. This results in an opposition to the sudden changes in current intensity. Inductors find use in frequency modulation in radios and for dampening voltage surges.
  • Resistors, as the name suggests, are used to control the flow of current or create a potential drop in a circuit, by resisting current. This current depends on the voltage provided by the source and on the dimensions and conductivity of the sample.
  • Transformers are used in electronic circuits to step down supply voltage before it is rectified into direct current. Transformers are also used for busting voltage spikes, as in constant voltage transformers (CVTs).

Active Components

Triacs, thyristors, silicon controlled rectifiers (SCRs), power supplies and various forms of transistors and diodes come under this class. Active components can be of thermionic nature also, as in valves and cathode ray tubes.

  • Semiconductor diodes namely SCRs, triacs, IGBTs, GTOs (gate turn off thyristors) consist of three conducting leads namely the anode, the cathode and the gate.
  • Triacs are semiconductor devices that allow the flow of current in either direction depending on the gate which is fired.
  • Thyristors and silicon controlled rectifiers (SCRs) allow current to flow in one direction only after the triggering of their gates.

Display systems

This is an important class of components often termed as the “eyes” of an electronic engineer. Cathode ray tubes, liquid crystal displays and light emitting diode displays come under this class.


These are devices that measure a physical quantity to a corresponding electrical value. Examples are pressure transducers, microphones, speakers and strain gauges.