Application

Most of us use electrical devices in our everyday life, and all of these electrical devices need a continuous flow of electric current to function. A power supply is the component that provides electricity in a circuit and the electricity that flows in a circuit is called current. When the power supply gets electricity to a socket,  the current obtained is called alternating current, these current is unstable and as these current enters in the power supply, it is slowly converted into a direct current(stable current) which is the electricity that flows in electrical devices or appliances. 

Concept of a simple circuit:

An electrical circuit is basically any path through which electric current, or electrons can flow. Here is an example of a simple circuit, it represents the switches we use in our houses.

                                                     Switched off

When the bulb is switched off, there is a gap in the path and the bulb does not light up. This is called an open circuit and electrical current cant flow through it. 

                                                    Switched on

But when the switch is on, it closes the gap in the circuit and the electrons flow, then the bulb lights up. It makes what is called a closed circuit.

Series and Parallel Circuit

- In a series circuit, all components are connected end-to-end, so the electric current has only one path to follow that's why all bulbs lighted at the same time.

- But if the circuit is open, current stops flowing through every part of the circuit and all of the bulbs would go out. In series circuit, all components have equal current flowing through them( I1=I2=I3). Total voltage is also equal to the sum of the individual voltages( Vt= V1+V2+V3).
-The fewer the bulb that is connected, the brighter each bulb will glow.

- In a parallel circuit, the current moves through separate branches.

-Even if one of the branches of circuit is broken, current still flows through the rest of the circuit. 
-Houses use parallel circuit that enables us to switch off our personal computer without turning the lights off at the same time.