What is exactly happening when AC power is being converted to DC energy?
In: Technology
The most important part is the bridge rectifier. We use little electrical one way valves (diodes) so that no matter the input voltage (+ on top or on the bottom) you always get positive voltage on one wire and negative on the other, [the wiki has a nice GIF showing this](https://upload.wikimedia.org/wikipedia/commons/3/34/Diodebridge-eng.gif)
Generally we will put a big capacitor on the output to store the energy. This capacitor takes the ups and downs that are coming into it and stores the energy so it just sits at the peak voltage.
Now you’ve got a constant voltage that you can use to power things or can step down to a low voltage using a DC-DC converter so you can get 5V for your phone or 3V for a little micro controller.
Old style boxes, the really heavy ones, used to put a step down transformer in the front to bring the peak voltage down from 170V (on US 120V power) to the 12 or 24V that they were needing in the end and then they ran that lower voltage through the rectifier and into the capacitor. These are simple and don’t require any fancy electronics but they do require about 5 pounds of iron in the transformer core. Electronics are wayyyy cheaper these days than they used to be so its now cheaper to use the fancy electronics for the DC-DC converter than a big transformer meant for stepping down line voltage at just 50/60 Hz
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