Flashcards
P6G Transforming
Cards in this deck (9)
- 1What is a transformer?A transformer can change the size of an alternating voltage - it doesn't change AC into DC. Transformers need AC to work - they do not work with DC.
- 2What is the difference between a step up and step down transformer?Step up - increase voltage, more coils on the secondary coil than on the primary coil
step down - decrease voltage, fewer coils on secondary coil than on the primary coil - 3What are step up transformers used for and what are step down transformers used for (1 example of each)?step down - phone chargers, laptops and radios
step up - increase voltage from power stations to national grid - 4Why can transformers only use AC?They rely on a changing magnetic field in the primary coil to induce a voltage in the secondary coil. Only AC current gives the changing magnetic field that the coils need.
- 5How does a transformer work?As the AC increases in the primary coil, the magnetic field it produces grows and cuts through the wire of the secondary coil and induces a current.
As the AC in the primary coil falls, the current in the secondary coil is induced in the opposite direction to try to support the magnetic field. - 6Look on pg 98 for more about the types of equations you needDO IT NOW
- 7Why do we use step up transformers when transporting electricity over transmission lines from power stations to the national grid?A higher voltage means there is less current meaning that there is less energy is wasted through heat loss due to resistance.
- 8How does an isolating transformer work and what are the benefits of one?An isolating transformer has an equal number of turns on the primary and secondary coils. This makes no difference to the voltage.
The benefit of having an isolating transformer is that it keeps the two halves of the circuit separate. Therefore, there is less risk of contact between the live parts and the earth lead. This means that the device is safer. - 9The power loss in transmission depend upon what and why is this important?It depends upon the current squared. This means if the current is halved then the power loss is only one quarter of what it was originally.
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- Flashcards on P6G Transforming, created by James Middleton8743 on 10/04/2015.
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- James Middleton8743
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