How do I ground various components (such as a voltage regulator) inside a device that won't be plugged into a grounded wall outlet?

 

They don't need ground!

 

The "ground" in such circuits is only a common reference point. It is a "chassis ground" instead of an "earth ground."

 

Or, if you are worried about safety when your device connects to AC operated equipment, shielding the circuit from ESD, or establishing a ground for your AM crystal radio, connect to the ground pin on a three pronged power plug, connect to a ground rod or other grounded metal structure such as a water pipe (if you live in a place old enough to have metal pipes that go into ground or concrete).

 

So I would just not connect the "ground" pin to anything?

 

You would connect the "ground" pin to "circuit ground." It's a just name, like "Peter," or "Madalyn." But though "Peter" means "rock," Peter is not actually made from stone. And many Madalyns have never even been to Magdala, even though their name means "from Magdala."

So the "circuit ground" need not be connected to "earth ground." It is simply a common point of reference for all the other voltages and signals.

 

OK thanks, that clears up a lot of confusion. One question that just popped up due to curiosity is, in a generator, how are the 120VAC outlets grounded, or are they?

 

They use the classic 3 prong system. Ground on the connector is a looong wire that goes to where ever your power tap off the grid is, and is usually about 3-6' of wire (or spike) going into the earth.

This article touches lightly on the subject, from a different point of view. I wrote it for the AAC book.

http://www.allaboutcircuits.com/vol_3/chpt_9/1.html

 

I don't think I was clear enough-I'm talking about portable generators such as those you might have during an emergency that provide power to cell phones, radios, flashlights, etc.