oh yeah, come to think of it, when I replaced the alternator on my '91 camry two summers ago, the voltage regulator is built in to the alternator! The way they regulate voltage is to change the bias in the stator windings. This is also why you can't push start a car with a dead battery, as there needs to be some type of voltage present to generate a voltage in the field windings.
Back in '77 I was driving from VA to MO and my battery light came on. I stopped at a service station in west VA to have my alternator checked (68 Chevelle). They said it was good, and we were baffled about what could be causing it, until another mechanic came over and said, "you have one more chance" and checked my regulator, which was mounted to the sidewall. It was bad, so I drove to a parts store and picked up a new one, replaced it in the parking lot, and was on my way. I still remember the old red brick buildings and the steep steep mountains right behind them.
Also, in '79, when I was stationed in CT, a friend bought a lobster boat that had sunk (halfway) in the harbor as the kid that owned it (his parents were in Europe) had let the battery run dead and the bildge pump quit working. The engine was a chrysler marine, and the electrical system was completely shot, including water in the voltage regulator box. I didn't know anything about MOPAR, so I bought all delco parts and re-wired the thing like a chevy. All we had to do was flush the engine, pour oil in each cylinder, and the thing started up and ran like new... whoo hoo... free lobster (for the summer, at least).
ahhh, the good ol' days (pre electronic ignition, electronic fuel injection, smog controls, and controller based timing advance) when you could work on your own cars!