Switch Mode Transformers operate at high frequency, between 50 kHz and 200 kHz.
They are used for charging mobile phones.
The main advantages of using switch mode transformers over other types of transformers are that they have a greater efficiency, they are smaller in size and lighter in weight.
They use only a small amount of power when they are switch on but no load is applied (they are plugged in but you are not charging your phone etc.)
