Series and Parallel circuits - examples
(A) Series circuit: Christmas lights are wired in series. If you pull out one of the light bulbs from a strand, the rest of the lights will 'switch of'.
(B) Parallel circuit: This is how our homes are wired. Each room has it's own parallel lighting circuit. So, even if one light bulb is pulled out, the other light bulbs stay lit.
Series and parallel connections
Circuits consisting of just one battery and one load resistance are very simple to analyze, but they are not often found in practical applications. Usually, we find circuits where more than two components are connected together. There are two basic ways in which to connect more than two circuit components: series and parallel.
Suppose there are three light bulbs to be connected in a circuit. In a series circuit, the light bulbs are arranged in a chain, so the current has only one path to take. Light bulbs can be added to the same chain, with no branching point. As more and more light bulbs are added, the brightness of each bulb gradually decreases. This observation is an indicator that the current within the circuit is decreasing. If one of three bulbs in a series circuit is unscrewed from its socket, then the other bulbs will not glow.
In a parallel circuit, the light bulbs are connected in two or more paths, so the current is divided into two or more paths to complete the circuit. For parallel circuits, as the number of light bulbs increases, the overall current also increases. This increase in current is consistent with a decrease in overall resistance. If an individual bulb in a parallel branch is unscrewed from its socket, then there is still current in the overall circuit in the other branches and the remaining bulbs will still glow.