In series circuits, electrical componentA device in an electric circuit, such as a switch or lamp. are connected one after another in a single loop.
Circuit rules
An electronSubatomic particle, with a negative charge and a negligible mass relative to protons and neutrons. will pass through every component on its way round the circuit. If one of the bulbs is broken then currentMoving electric charges, eg electrons moving through a metal wire. will not be able to pass round the circuit. If one bulb goes out, they all go out.
Learn more on series and parallel circuits in this podcast
A seriesA circuit where one component follows directly from another, eg three bulbs in a row with no junctions are said to be connected in series. circuit is one loop; all electrons in that loop form one current. An ammeterA device used to measure electric current. will measure the same current wherever it is placed in the circuit:
\(I_{1} = I_{2} = I_{3}\)
This is when:
current (I) is measured in amps (A)
If the resistance of any component in a series circuit changes, this will change the value of the current in the circuit.
Potential difference in series
The current will transfer energyThe capacity for doing work. from the power supply to the components in the circuit. Since energy has to be conserved, all of the source energy is shared between the components. Since potential differenceThe potential difference (or voltage) of a supply is a measure of the energy given to the charge carriers in a circuit. Units = volts (V). This is the voltage between two points that makes an electric current flow between them. is used to measure changes in energy, the potential difference supplied is equal to the total of the potential differences across all other components:
\(V_{s} = V_{1} + V_{2}\)
This is when:
potential difference (V) is measured in volts (V)
If the resistance of any component in a series circuit changes, this will change the potential difference across all of the components.