What is the difference between a step-up and a step-down transformer? Give examples where each would be used.

2 answers

The output voltage of a step-up transformer is greater than the input voltage.

The output voltage of a step-down transformer is less than the input voltage.

In each case, the input voltage is connected across the primary winding, and the output voltage is measured across the secondary winding.

If the turns ratio from primary to secondary was 1:4, the voltage across the secondary would be 4 times the primary voltage.
Radios and TV sets often use step-up transformers to increase the 120-volt line voltage.

Step-up and step-down transformers are also used for impedance matching for maximum power transfer. For example, a step-down transformer would be used to match a high resistance source to a low resistance load; and a step-up transformer would be used to match a low resistance source to a high resistance load.

I hope I've been helpful.