@ropbla9: The assumptions in your example don't make sense. We talk about voltages at certain points in a circuit as shorthand when it's clear what the reference is, but there's no such thing as 'potential of poles' in absolution; this is like measuring the length of a stick by only looking at one end. Likewise, saying the negative side of your 5 V battery is at +5 V is arbitrary and has no physical meaning. You also can't have a voltage difference over a direct connection. Connecting one diode terminal to a battery terminal means both are at the same potential, whatever you like to call it.

@vaxquis: Half a century is an understatement. 'Kilo' derives from the Ancient Greek word for thousand, predating SI by millenia.

Isn't a diode just as linear in first approximation?

I think the confusion is in the different interpretations of the resistance of 100 kΩ. That could refer to resistive losses - a reasonable way of looking at the quantity I²R when analysing the complexities of a motor, but when analysing the circuitry the motor is part of, 100 kΩ probably is the resistance of the component as a whole. In the latter case, I²R is not the power lost due to restitivity, but rather the total power supplied to the motor, which 'I²R losses' only partly account for.

@Telaclavo - The average current will be independent of frequency on any sufficient period of time, because it is (ideally) zero. Any non-zero value will mean charges are built up continuously and a gate cannot store an endless supply of charges. The absolute value however, is not. Higher frequencies imply the same charges are being moved to and from the gate at a higher rate, i.e. a higher absolute current.

Absolutely right. Moreover, even after the negative charge has redistributed itself, there will be still be microscopic currents everywhere in the material as charged particles are kept in motion by a non-zero thermal energy. We could go even deeper and discuss these motions based on quantum physics. That would hardly be circuit level anymore though.