What is a switching power adapter?

A power adapter Typically is an item that converts a 120VAC power signal into a much safer and lower DC signal that can range anywhere from 2 volts to 30 volts. Inside its guts, There is most likely a transformer, resistors, rectifiers, and Chips that control the current.

In case you do not understand,let me break it down:

120VAC enters into the adapter.

it enters into a step-down transformer.

this lower current enters a series of rectifiers that convert AC current into a safer and cleaner DC current.

This DC current enters a few resistors along the way.

Finally, this Much lower, cleaner, and safer current is transported out some wiring and to your laptop or other portable electronic.