Flashcards
transformers
Cards in this deck (11)
- 1How can a potential difference be induced in a metal wire (conductor) ?If an electrical conductor ‘cuts’ through a magnetic field a potential difference is induced across the ends of the conductor.
- 2How can a potential difference be induced in a coil of wire ?If a magnet is moved into a coil of wire a potential difference is induced across the ends of the coil.
- 3draw a diagram of a transformer
- 4Describe the structure of a transformer ?1. a laminated core made from iron
2. 2 coils
3. coils made from electrical conductor and coils covered in plastic insulation
4. coils are on opposite side
5. step up has more turns on secondary coil
6. step down has more turns on primary coil
7. step up output pd greater than input
8. step down output pd is lower than input - 5Explain the principle behind how a transformer works1. an alternating current creates a changing magnetic field
2. in the iron core
3. causing a potential difference to be induced across a secondary coil - 6Explain the difference between a step up and step down transformerIn a step-up transformer the potential difference across the secondary coil is greater than the potential difference across the primary coil.
In a step-down transformer the potential difference across the secondary coil is less than the potential difference across the primary coil. - 7what determines the power output of a transformer ?The input to a transformer is determined by the required output
- 8Between which frequencies do switch mode transformers operate ?Switch mode transformers operate at a high frequency, often between 50 kHz and 200 kHz.
- 9Compare switch mode transformers to traditional transformers.
- 10Which type of appliances are switch mode transformers useful for ?useful for applications such as mobile phone chargers
- 11Give an avantage of switch mode transformersSwitch mode transformers use very little power when they are switched on but no load is applied