Electricity: Direct and Altering Currents

Electricity: Direct and Altering Currents

  1. Direct Current (DC)
    • In direct current, the flow of electric charge is only in one direction.
    • It is commonly produced by sources such as batteries and solar cells.
    • It is used in electronic devices, for charging batteries, and for low-power devices.
  2. Alternating Current (AC)
    • Alternating current, unlike direct current, constantly changes direction.
    • AC current is produced by most power stations and is used in most homes and businesses.
    • The voltage in AC can be easily increased or decreased, making it more suitable for long-distance transmission.
  3. Mains Electricity
    • The UK mains supply is an AC supply at 230V and 50Hz.
    • It provides a high and steady voltage, suitable for running most electrical appliances.
  4. Comparing DC and AC
    • AC is more efficient for transmitting electrical power over long distances.
    • DC is more efficient and safer in terms of transmission for short distances.
    • AC can be converted into DC and vice versa using a power supply.
  5. Power and Energy
    • The power of an electrical circuit is given by the product of the voltage and the current. It’s measured in watts (W).
    • The energy transferred in a circuit is the product of the power and the time.
  6. Electrical Hazards
    • Electrical faults can lead to fires or cause electric shock.
    • Fuses, circuit breakers, and earth wires are safety devices used to prevent such hazards.
  7. Chargers and Adaptors
    • These are devices that convert AC to low voltage DC suitable for charging batteries or powering small electronic devices.
    • Poor quality chargers and adaptors may lack safety features, exposing users to possible harm.

Remember to recite these points, understand their application and consider how they might play into potential questions. Practice deriving information from diagrams and work on mitigation strategies for electrical hazards.

Responsibility for your own learning and revision habits will help you succeed. Refer back to specific lessons if additional detail is needed. Understanding rather than memorising will aid in retaining the concepts. Use as many tools as possible, like flashcards, mock tests, and revision guides, to aid your learning process. Remember that success requires persistence and hard work, so stay dedicated and keep revising. Regular breaks and keeping a positive mindset also contribute to effective revision. Best of luck with your preparation.