Question 14

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!

The transformer is a very simple device. It consists of three components, none which have any parts. There is a which is made out of soft iron. The word soft here means that the iron loses its magnetism very after the current has been turned off. The core is made up of many of iron, separated by an insulating layer. This is called laminated.

The coil is connected to the voltage source. The has a voltage induced by the changing magnetic field. The two coils are not electrically .

If DC is passed through the primary, voltage is induced at the secondary. Although the magnetic field is , it is not changing. Since the current in AC is all the time, the magnetic field is changing all the time. Therefore a voltage is induced. Therefore transformers work on AC, but not DC.