I went back through all my posts to see if I had ever said, "the plate
with the positive charge." I did not. I often said, "the positive
plate," but that is something entirely different.
When I label a capacitor with plus and minus signs, I mean the same
thing as when I label a resistor with plus and minus signs, or a battery
with plus and minus signs... namely, the plus indicates the
higher-potential side and the minus indicates the lower potential side.
For any of these circuit elements in an operating circuit, the + side
could be above ground potential and the minus side could be below ground
potential, but both sides could just as easily be below ground or both
sides could just as easily be above ground.
When I say "positive plate" I mean the plate at higher potential. It
may or may not have net positive charge. It may or may not be above
ground potential.
Michael D. Edmiston, Ph.D.
Professor of Physics and Chemistry
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu