Series Circuits

A series circuit is a circuit in which components are connected one after another in a single conducting path. Because there is only one path for charge to move through, the same current passes through every component in a series circuit.

For components connected in series: **I = I₁ = I₂ = I₃** The current does not split because there is no junction providing another path.

The total potential difference supplied by the source is shared among the components: **Vₜ = V₁ + V₂ + V₃** A component with a greater resistance receives a greater share of the total p.d. when the same current flows through all components.

The total resistance is: **Rₜ = R₁ + R₂ + R₃ + ... Adding another resistor in series therefore increases total resistance. From Ohm's law: I = VR** If supply voltage remains constant while total resistance increases, the circuit current decreases.

Three resistors of 2 Ω, 3 Ω and 5 Ω are connected in series. Rₜ = 2 + 3 + 5 **Rₜ = 10 Ω** If connected to a **20 V** source: **I = VR** **I = 2010 = 2 A The same 2 A** passes through all three resistors.

If one component breaks and creates an open circuit, the only conducting path is interrupted. Current therefore stops throughout the circuit.