I am trying to understand how computer PSUs work. I found the following circuit in Wikipedia and I noticed that, unlike the 12V and 5V outputs, there is no winding in the transformer for the 3.3V output. Instead, a coil is connected to the 5V secondary before the diode.
I have some experience in swith mode power supplies but I did not see this circuit before. How does this 3.3V output circuit work?