fighter electric power

ok guys here’s another question for all of you.

what is the source of electric power on modern fighter ac? if it just a massive battery charged pre-flight, or can the engines be used to generate electricity to recharge a smaller battery as the fighter is in flight?

if it is the former, would that impose restrictions on how long/far a fighter can operate even with ARF?

if the answer is the latter, which part of the fighter is the power generator located in? is it built into the engines or is there a seperate unit?

also, how big and heavy are the fighter’s power generators and does anyone have a picture if tehre is such a thing?

cheers