# Components of Electric Circuit

The elements or components of electric circuits are the ones that form the circuit in order to provide accurate circuit operation. The fundamental components of electric circuits are resistor, inductor, and capacitor.

## What is an Electric Circuit?

An electric circuit is defined as a closed-loop within which the flow of electric current takes place in the presence of the electric and magnetic field.  Basically, it is the electrons, the movement of which within the closed path causes the flow of current.

Now, there must be a question in your mind that from where these electrons come from and how their flow takes place.

So, every electrical circuit consists of a source which can be a simple battery or a complex generator. The electrons that flow within the circuit are energized by the source as it sets the electric field which gives rise to the electromotive force.

During the motion, once the electrons complete the path then they get grounded via load (output). This output of the circuit corresponds to the device which is required to be operated with the energization provided by the source. This can be a bulb, a TV, AC, cooler, refrigerator, charger, etc.

In its simplest form, an electrical circuit has a source, load and connecting wire which acts as a medium for the flow of charged carriers between the source and the load.

### Types of Electric Circuit

Mainly circuits are classified as:

1. AC circuits
2. DC circuits

The major differentiating factor between these two circuits is their type of energy source. The energy source utilized in AC circuits is an alternating current source whereas in the case of DC circuits the source is of direct current nature (i.e., constant source). Both these circuits have different applications.

An AC source offers variable voltage or current at different time instants while a DC source offers the constant value of voltage and current at different instants of time.

## Basic Circuit Elements

We have already mentioned that to compose any electric circuit, source, load and connecting wires are the necessary elements however, now we will discuss what are the other crucial components which are present in different types of basic electric circuits that help in the operation of the circuit efficiently.

In general, elements are classified as active and passive elements. Let us have a brief idea about both individually.

1. Active Elements: These are the elements that act as the unit that supplies the energy to the circuit. This can be a voltage source or a current source.

2. Passive Elements: The elements whose presence in the circuit helps in storing or dissipating energy are passive in nature. The three basic passive elements known in electrical circuits are resistor, inductor and capacitor.

Resistor: Resistor is a two-terminal element whose primary function in a circuit is to limit or reduce the flow of electric current flowing through the circuit. In the simplest terms, it is defined as the circuit element that offers resistance to the flow of current.

Symbolically a resistor is represented as: A resistor can be fixed or variable in nature. A fixed resistor is one that offers a predetermined value to the circuit and cannot be adjusted according to the requirement of the circuit. However, a variable resistor offers different values of resistance depending on the range provided by it and hence its value can be adjusted according to the need of the circuit.

For resistors, one should note that the size of the resistor shows direct proportionality with the power rating offered by it. We know power rating corresponds to the maximum power which the resistor can dissipate without getting damaged. So, when the surface area of the resistor is large then automatically its power rating will be high.

Inductor: An inductor is also a two-terminal element that opposes the change in the current but allows easy flow of steady-state direct current through the circuit in which it is present. Inductors consist of a coil of wire that exhibits the property of inductance. It is sometimes referred to as choke and utilizes the relationship between electricity and magnetism.

Symbolically inductor is represented as: When current flows through an inductor then it results in inducing a magnetic field. Basically, the magnetic flux produced within the coil is proportional to the current which flows through it. However, the generated magnetic flux will induce a secondary voltage within the coil which offers resistance to any further changes in the current which is flowing through it.

Capacitor: A capacitor is another crucial component of an electrical circuit that stores energy in the form of a charge when connected within a circuit. Basically, it has two plates that are separated by a dielectric material (which provides electrical isolation) and these plates hold the charges. It is a charge storing device.

The symbolic representation of the capacitor is shown below: The dielectric layer present between the two capacitive plates is non-conductive i.e., is of insulating nature hence do not allow direct current to pass through it when it is connected across an external voltage source. Due to this reason, the supplied energy in the form of charge gets deposited across the plates of the capacitor. But when the capacitor is connected across an alternating current source, then the current is allowed to flow offering less or no resistance.

There are some other components of electric circuits like diodes, transistors, etc. however, resistor, capacitor and inductors are the basic components of electric circuits.