Electricity

• Ammeter

  measures current in amps
• Earthing

  allowing charge or current to flow to the ground
• battery

  two or more cells together
• cell

  a source of electrical energy
• coulomb

  unit of electrical charge
• static electricity

  charge which is not moving caused by transfer of charge
• current

  the flow of electricity around a circuit (A)
• electric shock

  when electricity flows through the body
• electrical conductor

  a material that lets electricity through, low resistance
• electrical insulator

  a material that does not let electricity through, high resistance
• potential difference

  the difference in energy between 2 points in a circuit, (V)
• parallel circuit

  a circuit with 2 or more branches, same voltage on each
• power

  how quickly energy is transferred from 1 source to another
• resistance

  How difficult it is for electricity to flow
• national grid

  transformers, pylons and wires that link homes to power stations
• series circuit

  a circuit with only 1 loop of wires with voltage shared between components
• voltmeter

  measures pd/voltage between different points in a circuit
• voltage

  the energy carried by each unit of charge, sometimes interchangeable with pd
• how does conventional current flow?

  positive to negative
• how are ammeters connected

  in series
• how are voltmeters connected

  in parallel
• unit for current

  amps (A)
• unit for voltage/pd

  Volts (V)
• unit for resistance

  Ohms (Ω)
• in a series circuit the current is

  the same everywhere
• in a parallel circuit the current is 


  split between all the branches
• in a series circuit the voltage of each component sums to


  the voltage of the cell
• in a parallel circuit the voltage of all of the branches is

  equal
• when resistance is high current is

  low
• when resistance is low current is


  high
• resistance is affected by

  material, length of wire, thickness of wire and temperature
• when temperature is high resistance is

  high
• in a series circuit the total resistance is

  the sum of all the separate resistors
• in a parallel circuit the resistance is

  less than the smallest resistor
• ohms law

  current and voltage are directly proportional
• in a filament bulb the current and voltage are

  not proportional, the graph is "f" shaped
• diode

  an electronic component used to regulate pd in circuits and make logic gates. they have high resistance in 1 direction so current can only flow in 1 direction. We use them to turn AC to DC
• alternating current

  the current keeps changing direction
• earth wire

  earths current, 0V, green and yellow wire
• live wire

  carries current to device, 230V, brown wire