Series and parallel circuits

4.4.1 Circuit diagrams

4.4.3 Action & use of circuit components

Series and parallel circuits

  1. Series

    1. The current at every point in a series circuit is the same
    2. The sum of the p.d.s across the components in a series circuit is equal to the total p.d. across the supply
    3. The combined resistance of two or more resistors in series is equal to the sum of the resistances

  2. Parallel

    1. In a parallel circuit, the current from the source is equal to the sum of the currents in the separate branches of a parallel circuit
    2. The effective resistance of two or more resistors in parallel is equal to the reciprocal of the sum of the reciprocals of the resistances
    3. The advantage of connecting lamps in parallel in parallel is that if one blows, the rest of the circuit can still function, and the faulty lamp can be easily located and replaced