Components

• What do we need to draw circuit diagrams?

  Know component functions and symbols
• What is the purpose of a cell or battery in a circuit?

  To provide electric power to the circuit
• What does a switch do in a circuit?

  Controls the flow of electricity
• What happens when a switch is closed?

  Electricity flows through the circuit
• What happens when a switch is open?

  The circuit is no longer complete
• What is a filament lamp?

  A small bulb used in circuits
• What is the function of a fuse in a circuit?

  Breaks if too much current flows
• What is the purpose of a diode?

  Allows current to flow in one direction
• What is a light emitting diode (LED)?

  A diode that emits light when current flows
• Where are LEDs commonly found?

  In alarm clocks and traffic lights
• What is the function of an ammeter?

  Measures current in a circuit
• How is an ammeter connected in a circuit?

  Connected in series
• What does a voltmeter measure?

  Potential difference in a circuit
• How is a voltmeter connected in a circuit?

  Added in parallel
• What are resistors used for in a circuit?

  To provide resistance to current flow
• What are the two types of basic resistors?

  Fixed and variable resistors
• What is a light dependent resistor (LDR)?

  A resistor whose resistance depends on light intensity
• How does an LDR behave in bright light?

  Has low resistance allowing high current flow
• What applications use LDRs?

  Automatic night lights and burglar alarms
• What is a thermistor?

  A resistor whose resistance depends on temperature
• How does the resistance of a thermistor change with temperature?

  Higher temperatures decrease resistance
• Where are thermistors commonly used?

  In car engines and electronic thermostats
• What are the main components and symbols used in circuit diagrams?

  • Cell or battery: provides power
  • Switch: controls electricity flow
  • Filament lamp: small bulb
  • Fuse: breaks with excess current
  • Diode: allows current in one direction
  • LED: emits light when current flows
  • Ammeter: measures current (in series)
  • Voltmeter: measures potential difference (in parallel)
  • Resistors: provide resistance (fixed or variable)
  • LDR: resistance depends on light intensity
  • Thermistor: resistance depends on temperature