P3 - Transformers

Question 1

How does a transformer work?

Answer 1

A transformer works by sending an alternating current into the primary coil. This produces an alternating magnetic field which then flows around the soft iron core.

The secondary coil cuts the alternating magnetic field and this induces a potential difference.

Question 2

What is the difference between a step up and a step down transformer?

Answer 2

A step up transformer increases the voltage. (More turns)

A step down transformer decreases the voltage. (Less turns)

Question 3

What is a switch mode transformer?

Answer 3

A transformer which operates at high frequencies (between 50 kHz and 200kHz).

Question 4

What are the advantages of using switch mode transformers?

Answer 4

They are much lighter and smaller than traditional transformers which makes them useful for applications such as mobile phone chargers.

They also use only a very small amount of power when they are switched on but no load is applied (eg. phone charger plugged in with no phone) so they do not waste energy/electricity when not in use.