A Personal Force-field Generator is what it sounds like - a gadget that generates a force field that protects a single person. In the Whateleyverse, PFGs mostly seem to be devises. Not because force fields are outside of the laws of nature, because they aren't. It's more likely either that patentable single person force field generators have serious downsides, or they're too well known and hence too boring to make good projects.
Appearances[]
PFGs appear in a large number of stories.
A major part of the mess at the end of the 2006 Weapons Fair was caused by tightly packed PFGs.[1]