If I were to take a standard AC to DC converter, say a laptop charger, and hook up the input side (which expects 120VAC at 60Hz) to a DC power supply of some sorts, will the electricity still be “converted,” or will it just not work at all? I am clearly very uneducated when it comes to electronics (albeit working on it) so I would very much an ELI5 answer Thanks!
In most cases it will work fine as the first thing a good power supply does to the incoming electricity is converting the AC to DC using a full bridge rectifier. If you already supply DC, the current will just flow through it without a problem and the power supply simply continues to do its stuff.
However note that the DC input voltage needs to be relatively high. About sqrt(2)~=1.4 times as high as the rated AC voltage should be fine. So if you have a power adapter that’s rated for 120 to 240 VAC, you should give it something between 170 and 340 VDC. This is obviously very high (and dangerous). Plugging in a normal car battery or the output of a usb charger or something like that will likely do nothing.