In a recent post Help - I Need Somebody I asked for some help in explaining my ideas about a physics problem. It turns out I had a misconception. The short answer is that a particle that traverses an electric field and winds up at the same potential it started at will have the same energy it started with. 93143 was right all along. It took until Friday (from my post on Tuesday) for him to explain it well enough so that I got it. The above explanation should save him (and myself and others) a lot of time in the future.