Electricity

• Current is the flow of electrical charge
• Unit of current is amps
• Potential difference is the force that pushes the charge round. Measured in volts
• Resistance is anything that slows the flow down. Measured in ohms
• Charge through a circuit depends on current and time
• Charge flow(coulombs)=current x time
• Potential difference = current x resistance
• LDR is short for Light Dependent Resistor
• The resistance of a Thermistor depends on temperature
• Series Circuit

  P.D is shared

  Current is same everywhere

  Resitance of all components adds up to total resistance
• Parallel Circuits

  P.D is same across all components

  Currents is shared between branches
• Mains supply is ac

  Battery supply is dc
• What is voltage and frequency of Uk main supply

  230v and 50Hz
• Live wire provides alternating potential difference at 230v
• Neutral Wire completes the circuit. Its 0v
• Earth Wire is for protecting wiring and saftey. 0v
• Neutral- Blue

  Live- Brown

  Earth- Yellow and Green
• Energy transferred= Power x Time
• Energy transferred = charge flow x potential difference
• Power= Potential Difference x Current

  Power= P =I2R