Why are power adapters and chargers getting smaller and smaller?

In the past, power adapters generally used linear power supplies, which required a very bulky transformer to provide sufficient inductive reactance, so the power adapter was very bulky. Today's power adapters and chargers generally use modern electronic technology. The switching power supply technology directly rectifies the 220V AC power to obtain a signal similar to a square wave. Without the bulky transformer, the volume can naturally be made smaller.

The gallium nitride charger has pushed the charger volume to a new height, with small size, light weight, low calorific value and high conversion rate. Without power adapters, there would be no later chargers, and without advances in material science, it would be impossible to make power adapters and chargers small.