Power supply

The power supply is more complex, and I will attempt to describe each component.

Outermost is the Electromagnetic Interference (EMI) filter. It filters unwanted electromagnetic waves, including radio frequencies, which can be caused by such things as AC motors and even power cords.

Next is a half-bridge rectifier, which simply changes AC to DC. There is some voltage drop over the diodes, but it is only significant in low voltage power supplies, which this isn't.

Then comes the power factor controller (PFC). The PFC needs a controller circuit, and understanding how it works is a bit more in depth than I understand. To summarize though, it puts voltage and current waveforms back in step in reactive loads, increasing the power factor to approach a value of 1. Any power factor less than 1 means that the circuit is not utilizing all of each waveform, and runs much less efficiently.

After this is a half-bridge. It's an IC controlled circuit that lets you apply a voltage across a load in either direction. I'm not entirely sure why this component is necessary, unless it's to act as a sort of rectifier.