Understanding Transformers: How they Change Voltage and Current

The video tutorial explains how transformers work, focusing on their ability to change the size of an alternating potential difference. It covers the structure of transformers, consisting of primary and secondary coils wound on a common iron core, and how they induce a potential difference. The tutorial also discusses the relationship between the potential differences and currents in the coils, using equations to demonstrate these concepts. An example calculation is provided to illustrate how to determine the potential difference and current in a transformer, assuming 100% efficiency.

What is the primary function of a transformer in an electrical circuit?

• To convert direct current to alternating current

• To measure electrical resistance

• To change the size of an alternating potential difference

• To store electrical energy

How are the primary and secondary coils of a transformer related?

• They are connected in series

• They are connected in parallel

• They are wound on a common iron core

• They are electrically isolated

What happens to the current when the potential difference is stepped up in a transformer?

• The current remains the same

• The current is stepped down

• The current is converted to direct current

• The current is stepped up

In a 100% efficient transformer, what is the relationship between input and output power?

• Output power is unrelated to input power

• Output power is greater than input power

• Output power is less than input power

• Output power equals input power

If a transformer has 4000 turns on the primary coil and 200 turns on the secondary coil, what is the potential difference across the secondary coil if 240 volts is applied to the primary coil?

• 24 volts

• 6 volts

• 12 volts

• 48 volts