Electricity

• How does static charge move

  friction builds up in one place.

  induces a potential difference

  causes air to ionise

  ionised air conducts the charges in a spark
• what is an electron

  charged particles that move around a circuit carrying energy

  Group of electrons is called Coulomb
• what is potential difference (Volts)

  amount of energy (Joules) given to each coulomb of charge
• what is current

  How fast the charges (electrons) move around a circuit
• what is Resistance (Ohms)

  Restriction of the flow of electrical current
• what is a voltmeter symbol


  .

  
• symbol of LDR and function

  Light

  Up

  Resistance

  Down

  
• symbol of thermistor and function

  -varies resistance with temp.

  Temperature

  Up

  Resistance

  Down

  
• symbol of diode and function

  only allows current to flow in one direction

  
• what is the circuit rule of Current in series

  They are same/equal at all positions
• what is the circuit rules of current in parallel

  total current is the SUM on each branch
• what is the potential difference of series

  Total potential difference is the SUM of p.d. on each component
• what is the circuit rules potential difference of parallel

  same/equal on each branch
• what is the circuit rules of resistance of series

  total resistance is the SUM of each resistance
• what is the circuit rules of resistance in parallel

  total resistance is always less than the smallest resistor
• what is the fixed resistor iv graph shape

  a straight line gradient = constant resistance

  
• what is the diode iv graph shape

  no current then a low resistance of a very steep line

  
• what is filament bulb iv graph shape

  changing gradient= changing resistance

  low resistance then high resistance

  
• what is thermistor iv graph shape

  when thermistor is cold a shallow gradient = more resistance

  when thermistor is hot a steeper gradient = less resistance

  
• what is LDR iv graph shape

  when bright light there is steeper gradient = low resistance

  when dim light there is shallow gradient = high resistance

  
• what is Direct Current

  Current that flows in the same direction all the time, from positive and negative
• examples of Direct Current

  Batteries & Solar cells
• what is Alternating Current

  moves forwards and backwards repeatedly

  terminal p.d. changes from +V to -V with each oscillation
• what is uk AC mains

  230V
• what is AC frequency

  50Hz = alternates 50Hz a second
• what is DC source graph

  constant same current flow

  
• what is AC source graph

  Alternates current moving

  
• what is the colour of neutral wire

  bLue (left)
• what is the colour of Live wire

  bRown (right)
• what is the colour of earth wire

  green/yellow
• function of live wire

  carries the electricity in the device
• function of neutral wire

  completes the circuit and electricity goes out and operates at 0V
• function of earth wire

  a safety wire to stop the appliance becoming live and recieving a electric shock if made from metal
• what is the National grid

  network of cables and transformers that carry electricity between power stations and our homes