Components of an electric circuit can be connected in different ways. The two simplest of these are called series and parallel. A circuit composed solely of components connected in series is known as a series circuit; whereas one connected completely in parallel is known as a parallel circuit.
Let us take a look at the components of a very basic electric circuit. There is a voltage source that produces the pressure to push electrons around the circuit. A battery that produces 1.5Volts acts as voltage source. As electrons start moving around, they collide with atoms. This slows down or obstructs the flow of electrons. The wire is said to offer resistance to the flow of current. The resistance offered depends on the material, length and diameter of the wire. As the diameter decreases, resistance increases.
Based on conductivity, there are two types of circuits – Open and short circuits. Open circuits do not conduct electricity because current can flow only in loops. Short circuit is a low resistance path which allows large amount of current to flow. This is quite dangerous as they generate lot of heat and cause fire. When two bare wires touch each other, short circuit happens.
Based on the connection, circuits could be classified as series and parallel circuits. In a series circuit, same current flows through all components. Voltage across each resistor is different. If one resistor burns out or does not allow current, no current further flows.
Example of series circuit is serial lights. If one bulb doesn’t work, then none of lights will glow. Total voltage is equal to sum of voltage across each resistor.
When resistors are connected in parallel, the voltage across each of them is the same. Current that flows through them are different. Total current is equal to sum of currents through each resistor. Example of parallel circuit is wiring done in houses. Source supplies same voltage to different appliances. If one appliance goes off, current still flows through other devices.