series and parallel circuits

• In a series circuit, the total resistance is the sum of the resistances of the components
• In a parallel circuit, the total resistance for two resistors is less than the resistance of the smallest resistor
• In parallel circuits, electrical components are connected alongside one another, forming extra loops
• An electron will not pass through every component on its way round the circuit in a parallel circuit
• If one of the bulbs in a parallel circuit is broken, the current will still be able to flow round the circuit through the other loop
• The current in a parallel circuit splits as it leaves the cell and passes through one or the other of the loops
• An ammeter is a device used to measure electric current in a circuit
• In parallel circuits, the current splits and an ammeter placed in different parts of the circuit will show how the current splits: \(I_{1} = I_{2}+I_{4} = I_{3}\)
• Since energy has to be conserved in a parallel circuit, the energy transferred around the circuit by the electrons is the same whichever path the electrons follow
• The potential difference supplied in a parallel circuit is equal to the potential differences across each of the parallel components: \(V_{s} = V_{1} = V_{2}\)
• If resistors are connected in parallel, the supply current is divided between them, reducing the overall resistance as the current may follow multiple paths
• Key fact about parallel circuits:

  • The total current supplied is split between the components on different loops
  • Potential difference is the same across each loop
  • The total resistance of the circuit is reduced as the current can follow multiple paths
• In series circuits, electrical components are connected one after another in a single loop
• An electron will pass through every component on its way round the circuit in a series circuit
• If one of the bulbs in a series circuit is broken, the current will not be able to flow round the circuit
• If one bulb goes out in a series circuit, they all go out
• In a series circuit, all electrons in the loop form one current
• An ammeter is used to measure electric current in a series circuit
• The current in a series circuit is the same wherever the ammeter is placed: \(I_{1} = I_{2} = I_{3}\)
• The potential difference supplied in a series circuit is equal to the total of the potential differences across all other components: \(V_{s} = V_{1} + V_{2}\)
• When resistors are connected in series, their resistances are added together: \(R_{total} = R_{1} + R_{2}\)
• Key facts about series circuits:

  • Current is the same through each component
  • The total potential difference of the power supply is shared between the components
  • The total resistance of the circuit is the sum of individual resistors