Series and Parralel

• what is a series circuit?

  • All components are joined in a single path
  • current is the same at all points
  • total pd is SHARED between all components
  • total resistance is the SUM of the resistance of each component

  I = I1 + I2
• what is a parallel circuit?

  • The total current is the SUM of all the different currents - not evenly distributed
  • pd across the circuit is the SAME
• what are resistors like in series

  the total resistance is equal to the sum of their individual resistances
• What are resistors in parallel

  if two or more resistors are connected in parallel, the combined resistance decreases

  • this is due to each resistor creating an extra path for charge to flow - allows more charge and a smaller resistance
• what is a DC circuit

  • current that is steady and constantly flowing in the same direction from p->n
  • batteries and cells produce a DC current
• what are disadvantages of series circuits

  • if one component breaks, all of them will stop working
  • the individual components cant be controlled
• what is AC current

  • a current which continulously changes direction
  • the uk mains is an ac current
• what is the frequency of the uk mains

  50 Hz
• what is the potential difference of uk mains

  230 V
• What is the mains electricity?

  • the electricity generated by power stations and transported around the UK via the national grid
  • does not have a positive and negative side to the power source, but instead live and neutral parts at the end of the circuit
• what is the live wire?

  • BROWIN
  • carries the alternating PD from the mains supply to a circuit
  • dangerous and can cause electrocution
• what is the neutral wire

  • BLUE
  • forms on the opposite end of the live wire
  • provides a path for the left over electricity to flow back to the power source
• what is the earth wire

  • GREEN and YELLOW
  • a safetey wire which prevents the appliance from becoming live
• what voltage do all the wires carry?

  live wire - 230 V

  neutral - 0V

  Earth wire - 0V
• what are the dangers of Mains electricity?

  • if a live wire came into contact with the case, the case would be electrified - leads to electrocution
  • the earth wire prevents this by fusing and melting if it comes into contact with current, making the casing safe to touch
• what happens in a parralel circuit when all the switches close

  • the total resistance decreases
  • so the current increases
  • so the power output increases