P3.10 AC & DC Current

• What are the two types of current mentioned?

  Alternating current (AC) and direct current (DC)
• How does alternating current (AC) behave?

  The direction of the current constantly swaps
• What causes alternating current to fluctuate?

  Alternating potential difference or voltage
• What happens to the charge flow in an AC circuit?

  It constantly swaps back and forth
• What is the frequency of the UK main supply electricity?

  50 hertz
• What is the voltage of the UK main supply electricity?

  Approximately 240 volts
• How does the potential difference fluctuate in the UK main supply?

  From positive 240 volts to negative 240 volts
• Why might you hear the voltage referred to as 230 volts instead of 240 volts in the UK?

  Both values are correct for exams
• What is direct current (DC) produced by?

  A direct potential difference
• How does the charge flow in direct current (DC)?

  It flows in the same direction
• Where do we commonly find direct current (DC)?

  In cells and batteries
• What devices are used to obtain potential difference time graphs?

  Oscilloscopes
• What are the key characteristics of alternating current (AC) and direct current (DC)?

  • AC:
  • Direction constantly swaps
  • Produced by alternating voltage
  • Found in mains electricity (e.g., UK: 50 Hz, 240 V)

  
  

  • DC:
  • Direction remains constant
  • Produced by direct voltage
  • Found in batteries and cells
• What is the significance of oscilloscopes in electrical measurements?

  • Used to display potential difference time graphs
  • Helps visualize fluctuations in current and voltage
• What is alternating current?


  An alternating current is a current that periodically reverses its direction.

  Effectively, it keeps changing/alternating its direction.
• What is direct current?


  A direct current is a current that always travels in the same direction around a circuit.
• What creates an alternating current?


  An alternating voltage, for example from mains electricity.
• What creates a direct current?


  A direct voltage for example from a battery or cell.
• What is mains electricity?


  Main electricity is the electricity generated by power stations and delivered to homes via the national grid.

  We access it by plugging devises into wall sockets.
• What is the frequency of mains electricity?


  50 Hz
• What is the voltage of mains electricity?


  230-240 volts
• What will an oscilloscope trace look like for an alternating current?


  (The oscilloscope trace would look the same for both current and voltage)

  
• What will an oscilloscope trace look like for an directing current?



  The current or voltage could be either positive or negative, depending on which way the current is travelling.

  (The oscilloscope trace would look the same for both current and voltage).