electricity

• what do circuits contain?

  A closed loop that contains a power source such as a cell and something for electrons to flow through (cell)
• what is a battery made up of?

  2 or more cells
• what is current (I)?

  The measure of the flow of electrons around a circuit
• What is potential difference?

  force driving flow of electrons
• Resistance (ohms)?


  everything that opposes the flow of electrons
• what is an ammeter?


  Device to measure electric current
• what is a voltmeter?


  Device to measure voltage.
• What is an LDR?

  Light Dependent Resistor
• What is charge?


  a measure of the total current that flowed within certain period of time
• what is contained in a series circuit?

  single loop

  componants conected one after the other
• what is contained in a parallel loop?

  more than one components
• what do you use to measure the current?

  ammeter
• what does ohms law state?

  components with a greater resistance will always have a higher share of voltage in parallel loops that have greater resistance
• what does charge mean?

  a measure of the total current that flowed within a certain period of time
• What is the national grid?

  A giant network of transformers that spreads across the country to distribute electricity
• What is the grid made of?

  transformers, wires and pylons
• What does a step up transformer do?

  increase voltage

  minimise energy
• What does a step down transformer do?

  lower voltage
• What does alternating current mean?


  direction of current constantly swapping back and fourth

  used when use alternating potential difference
• what is direct current?

  Produced by a direct protential difference

  either positive or negative

  charge always flowing in same direction

  in cells/ batteries
• What are fuses and circuit breakers?

  break the circuit when the current is too high

  fuse is very thin wire connected to live wire

  if surge- a huge amount of current will flow through live wire and fuse

  causes fuse to heat up quick- melt because too thin and break circuit
• what is the main way that surges cause harm?

  if the wire becomes loose inside appliance and can touch casing
• What is the main way of preventing an electric shock?

  earthing

  where an earth wire provides an alternating pathway for the current to flow away
• what are plugs and wires made from?

  copper so they can conduct electricity

  coated with insulating plastic for safety
• what are the 3 main wires in a plug?

  Live, neutral, earth
• what is the properties of the live waire?

  brown

  provides alternating potential difference

  230v from mains supply
• what are the properties of a neutral wire?

  blue

  acts to complete the circuit by carrying away current

  0v
• what are the properties of an earth wire?

  striped green and yellow

  doesn't normally carry current

  0v

  role is to stop the appliance casing for becoming live
• What does difference in voltage mean?

  causes electricity to pass from one thing to another
• what are sensing circuits used for?

  turn on or increase the power to components depending on the conditions they are in