Current

• Current is the flow of electrical charge.
• Potential difference is the driving force that pushes the charge round the circuit. Unit = Volts
• The greater the resistance across a component the smaller the current that for a given potential difference across the component
• Charge flow (C) = Current (A) x Time (S)
• Potential difference = Current x Resistance
• Ammeter :

  Measures the current

  Must always be placed in series with whatever you are investigating
• Voltmeter :

  Measures the potential difference

  Must always be placed in parallel around whatever your investigating
• IV Characteristics

  Shows how the current flowing through a component changes as the potential difference across it is increased
• Parallel circuits

  Each component is separately connected to the positive and negative of the supply. If removing one of them it will hardly affect the others at all.
• Potential difference is the same across all components
• Current is shared between branches of a circuit, so the total current is the sum of the currents in each branch.
• Adding a resistor in parallel reduces the total resistance