Invisible Power!

The invisible energy running this car is called the electrical energy. It is transferred to the car through the wires connecting on the inside of the car. Electric current flows through these wires.

The path through which the electric current travels is called the electric circuit.

Here are a few commonly used components of the electrical circuit.

Connecting Wires

Electric Cell

An electric cell has two terminals, one positive and the other negative terminal.

Electric Battery

When two cells are joined together via connecting wires in such a way that the positive end of one cell is joined the negative end of another cell.

This arrangement is called a battery. Thus, a battery is a combination of two or more cells.

It stores chemical energy and makes it available in electrical form.

Like a cell, battery also has two electrical terminals.


We use a switch, also called a key to connect or disconnect the circuit.

Also, called switching ON (connecting) or OFF (disconnecting).

In the ON position, the current starts flowing in the circuit and the light glows.

In the OFF position the current does not flow and the light doesn't glow.

Switch is an important component of the circuit, as it can be placed anywhere.

Connecting Wires

Substances which allow electric charge or electric current to pass through them are caled conductors of electricity.

Metals like silver, copper, aluminium,etc are good conductors of electricity.

Thus, wires are made of these metals, and are used as conducting wires.

Device - Bulb

Any appliance or device uses electric current for some useful purpose.

Circuit diagram

In an open circuit diagram the switch is in OFF position.

Since, in a closed circuit, current flows from the positive terminal to the negative terminal of the battery, arrows are marked to show the flow.

There should be a electric source, such as battery or a cell in the circuit.

There should be a device or an appliance connected to consume electricity.

There should be a conductor in the form of electrical wires to provide a path for the flow of current.

There should be a switch to open and close the circuit.

There should be no gap in the electric circuit for smooth flow of current.

Access All Content

Video Explanations, Practice Worksheets and Solved Examples for all Chapters.
Textbook solutions, Formulae and Mindmaps across all boards.

More from Grade 8 Physics

Heating Effect of Electric Current

Understand the concept of heating effect of electric current. See real world examples where this effect is observed.

Magnetic Effect of Electric Current

Understand the concept of magnetic effect of electric current. Demystify this seemingly magical effect. See it's application in the real world.

Electric Circuit

Understand the basic components of a electrical circuit using an exciting video of RC car.