Components

• Drawing circuit diagrams


  1. Know what the different components do

  2. Know the symbols used to represent them
• Cell


  Provides electric power to a circuit
• Battery


  Provides electric power to a circuit
• Switch


  • Controls the flow of electricity
  • Can be closed allowing electricity to flow
  • Can be open which turns off the circuit
• Filament lamp


  Small bulb
• Fuse


  Breaks if too much current flows through the circuit
• Diode


  Only allows current to flow in one direction
• Light emitting diode (LED)


  Emits light when current flows through in the forward direction
• Ammeter


  Measures current and is connected in series
• Voltmeter


  Measures potential difference and is added in parallel
• Resistor


  • Can be fixed to provide a certain number of ohms worth of resistance
  • Can be variable to easily modify the amount of resistance
• Light dependent resistor (LDR)


  • Resistor whose resistance is dependent on the intensity of light
  • Low resistance in bright light, high resistance in darkness
• Thermistor


  • Resistor whose resistance is dependent on the temperature
  • Higher temperatures cause resistance to fall, lower temperatures increase resistance
• LDR in bright light


  Very low resistance, allowing lots of current to flow
• LDR in darkness


  Very high resistance, hardly any current flows
• Higher temperatures


  Thermistor resistance falls
• Lower temperatures


  Thermistor resistance increases