Capacitors exist everywhere. Nature has evolved nerve cells of which
the axons are capacitors of a sort!
By creating a capacitor (cell membrane) and an Electric Field between the
surfaces of the cell membrane we are able to store energy in the Electric
Field for later use. We transform the energy in the Electric field
to energy of motion.
Electric
Potential Energy (U = EPE)
Work required
to move a charge in an Electric Field For the axon (nerve cell) to propagate an electrical signal, it must
store energy. That stored energy is in the form of an Electric Field. The
cell membrane is a capacitor. The Electric Field is created from the concentration
of ions inside and outside the cell membrane. Now, all the cell has to do
is allow the concentrations to change. This requires work.
Potential
(Volts)
notice that Potential is not Potential Energy!
W
is Electric Potential Energy (Joules)
is not
V is Electric
Potential (Joules/Coulomb)
a.k.a Voltage, Potential Difference
Equipotential
Surfaces
No work is required
for a charge to move along an equipotential surface. Work
is required for a charge to move to a different equipotential surface.