ACDC

• What are the two types of current mentioned in the study material?

  Alternating current (AC) and direct current (DC)
• How does the direction of current flow in alternating current (AC) behave?

  The direction of the current constantly swaps back and forth.
• What causes alternating currents to occur?

  They occur whenever there is an alternating potential difference or voltage.
• What does measuring potential difference or current over time reveal about alternating current?

  It shows that they constantly fluctuate between negative and positive.
• What type of current is supplied by UK mains electricity?

  Alternating current (AC)
• What does the fluctuation of potential difference in UK mains supply electricity indicate?

  It fluctuates from positive 240 volts to negative 240 volts and back again 50 times every second.
• What is the frequency and voltage of UK mains supply electricity?

  50 hertz and around 240 volts
• Why might you hear that the voltage in the UK is 230 volts instead of 240 volts?

  Both 230 volts and 240 volts are correct as far as exams are concerned.
• How does direct current (DC) differ from alternating current (AC)?

  DC is produced by a direct potential difference that is either positive or negative all the time.
• Where can direct current (DC) typically be found?

  In cells and batteries, such as those in phones or calculators.
• What device is used to obtain potential difference versus time graphs?

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

  • AC:
  • Direction constantly swaps
  • Found in mains electricity
  • Voltage fluctuates between positive and negative
  • DC:
  • Direction remains constant
  • Found in batteries and cells
  • Voltage is either positive or negative all the time