At this point, the Fermi levels for the two metals are equal, and there is no voltage difference between them.

If any node sets a voltage difference, all nodes will see it.

When current is driven through the capacitor, it takes a period of time for a charge to build up to produce the full voltage difference.

The flow of charge carriers between the hot and cold regions in turn creates a voltage difference.

Different systems are used to minimize the voltage difference between neutral and local earth ground.

The combs are arranged so that they never touch (because then there would be no voltage difference).

I. The output attempts to do whatever is necessary to make the voltage difference between the inputs zero.

Nothing bad happens as long as the two wires that have the big voltage difference between them do not meet.

Another way to think of his is that the current that results from a voltage difference must have a path in which to flow.

Between points with a low voltage difference, direct current can be controlled by a switch.