components of a circuit

• cell

  used to push electrons around circuit
• battery

  number of cells joined together, used to push electrons around circuit
• switch

  enables current in a circuit to be switched on or off
• bulb or lamp

  lights up when current passes through it, so can be used to indicate that current is flowing through the circuit
• fixed resistor

  limits amount of current flowing in circuit
• variable resistor

  allows the current in the circuit to be varied
• ammeter

  measures current in circuit
• voltmeter


  measures potential difference across a component in a circuit
• diode


  allows current to flow through a circuit in one direction only
• light emitting diode (LED)

  emits light when a current passes through it
• thermistor


  used as a temperature sensor in a circuit, as the temperature increases, the resistance of the thermistor decreases
• ohms law

  law that states that the current through a conductor is proportional to the potential difference across it, provided the temperature remains constant
• ammeters are always placed in series with other components in a circuit
• voltemeters are always placed parallel across a component in a series
• resistors can become hot when voltages are high, do not touch resistor straight after touching practical wait for cool down