Power adapter

A power adapter, comprising:

• a main circuit board, having a first surface and a second surface opposite to each other, wherein the first surface of the main circuit board is configured with a transformer and a first capacitor;
• and
• an auxiliary circuit board, having a first surface and a second surface opposite to each other, wherein the first surface of the auxiliary circuit board is configured with an input rectifier filter circuit, wherein the input rectifier filter circuit comprises an input terminal, an electromagnetic interference filter circuit and a rectifier element,
• wherein the auxiliary circuit board is disposed in parallel above the main circuit board, circuit wirings from electronic components on the second surface of the main circuit board are disposed on an overlapped region between the auxiliary circuit board and the first surface of the main circuit board, the first surface or the second surface of the auxiliary circuit board faces the first surface of the main circuit board, components of the electromagnetic interference filter circuit are disposed between the first surface of the auxiliary circuit board and the first surface of the main circuit board or disposed away from the first surface of the main circuit board, and the input rectifier filter circuit of the auxiliary circuit board is electrically connected to the first capacitor of the main circuit board.