electricity P2

• Parallel circuit


  A circuit that contains branches, where the current splits and passes through multiple paths
• Current flow in a parallel circuit

  1. Current splits and passes through multiple branches

  2. Current in each branch adds up to the total current leaving the cell
• Conventional current


  The direction of current flow as defined by scientists, which is opposite to the actual flow of electrons
• Ammeter


  A device used to measure the electric current in a circuit
• Series circuit


  A circuit where the current can only flow in one part, and the current is the same all the way around
• Current in the branches

  Adds up to the total current leaving the cell
• In a parallel circuit, the current in the branches adds up to the total current leaving the cell
• Parallel circuit


  A circuit that contains branches, where the current splits and passes through multiple paths
• Current flow in a parallel circuit

  1. Current splits and passes through multiple branches

  2. Current in each branch adds up to the total current leaving the cell
• Ammeter


  • Measures the current in a circuit
• Series circuit


  The current is the same all the way around the circuit
• Parallel circuit


  The current splits and passes through multiple branches
• The current in the branches adds up to the total current leaving the cell in a parallel circuit
• Potential difference


  The energy transferred per unit of charge moving through a circuit
• Measuring potential difference


  1. Connect a voltmeter across the component

  2. Read the voltage displayed on the voltmeter
• Potential difference across a cell


  Indicates the total energy transferred per unit of charge moving through the circuit
• Potential difference across components in series

  The total potential difference is shared between the components
• Potential difference in series circuits

  • The total potential difference is the same across all components
  • The potential difference across each component depends on the component's resistance
• The total potential difference across the series circuit is the same as the potential difference across the cell
• Potential difference


  Tells us about energy transfers taking place in a circuit. One volt of potential difference means one Joule of energy is transferred for each Coulomb of charge moving through the circuit.
• In a series circuit, potential difference is split between components.
• Parallel circuit


  Has branches, and some of the current passes through each branch.
• In a parallel circuit, the potential difference across each component is the same.
• Measuring potential difference in a parallel circuit

  1. Use a voltmeter across the cell

  2. Use a voltmeter across the branches
• Potential difference measurements in a parallel circuit

  • Cell potential difference is 6 volts
  • Top lamp potential difference is 6 volts
  • Bottom lamp potential difference is 6 volts
• When components are connected in parallel


  The potential difference across each component is the same
• Battery


  Two or more cells connected together
• Cells in a battery must be connected in the same direction
• Potential difference of a battery

  The sum of the potential differences of the individual cells
• Battery with two 9V cells

  • Total potential difference is 18V
• Calculating potential difference of a battery

  1. Multiply the potential difference of each cell by the number of cells connected in the same direction

  2. Subtract the potential difference of any cells connected in the opposite direction
• Battery with three 9V cells

  • Total potential difference is 27V
• Battery with two 9V cells, one reversed

  • Total potential difference is 0V
• Battery with three 9V cells, two in same direction


  • Total potential difference is 9V
• Electric charge

  Measured in coulombs (C)
• Current of 1 ampere

  1 Coulomb of charge flowing per second
• Electric current

  The rate of flow of electrical charge
• Calculating charge flow in a circuit

  Charge flow (C) = Current (A) x Time (s)
• Calculating current from charge flow and time

  Current (A) = Charge flow (C) / Time (s)
• Calculating total energy transferred by components

  1. Calculate total charge flowing in circuit

  2. Use equation: Energy transferred (J) = Charge flow (C) x Potential difference (V)

  3. Apply equation to specific components