Series parallel circuits are combined electrical circuits with both series and parallel configurations within one circuit. In series-connected sections of a series parallel circuit, current flows in one path but splits to different paths when it reaches parallel-connected segments.
Analyzing series parallel circuits requires an understanding of the rules governing the separate series and parallel circuits. Elements in a series circuit share equal currents and the sum of their voltage drops equals the supply voltage. The overall resistance in a series circuit is the sum total of the individual resistances. Conversely, elements in a parallel circuit have equal voltage drops and the current of the outside branch equals the total of currents flowing in the branches. The reciprocal of the equivalent resistance in a parallel circuit equals the sum of the reciprocals of the individual resistances.
Separating the series segments from the parallel segments of series parallel circuits enables the application of the governing circuit rules. Analysis involves finding the equivalent resistance of the parallel segment and adding it to the series resistance. This results in a series circuit whose sum of voltage drops across the elements equals the supply voltage. Consequently, applying Ohm’s law makes calculation of currents and voltage drops across each element easy.