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Correct me if I'm wrong on this, but up till now I've assumed that the voltage across a resistor could be seen as both the energy lost by a current passing through it and the energy needed for a current to pass through it in the first place. Does this apply to the voltage across reactive components (inductors and capacitors) as well?

Or is it right to think that these components do not require energy expenditure as they offer no REAL resistance, so their voltages are not actually the driving force necessary for the current's passage across them but rather a counter voltage that could be generated at some time before or after this passage therefore can lead or lag behind?

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    $\begingroup$ Clearly it does not apply to reactive components - they are called reactive because of the phase differences between voltage and current in their operation. $\endgroup$
    – Jon Custer
    Commented Apr 6, 2016 at 13:47
  • $\begingroup$ To add a little color to Jon Custer's comment: "perfect Ohmic resistors" don't exist. In reality a resistor has, at the very least, a capacitive and an inductive component and usually it's even more complex than that if we are interested in a really wide range of frequencies. Wether one has to consider these stray elements or not depends on the application. $\endgroup$
    – CuriousOne
    Commented Apr 6, 2016 at 15:28

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Or is it right to think that these components do not require energy expenditure as they offer no REAL resistance, so their voltages are not actually the driving force necessary for the current's passage across them

The energy expenditure is needed, but the energy is stored in the EM field and can be released later, so it is not lost to heat like in resistor.

The driving force that is responsible for the electric current is electric force, which is determined by difference of electric potentials in DC circuits, but is not so determined inside the wire of a solenoid or capacitor. The electric field is not, in general, given by electric potential.

For example, in a solenoid electric field in a wire element can be thought of as sum of the electric field of the power source and the wires that connect to the solenoid and the electric field due to solenoid itself. In case the current is oscillating, the induced electric field of the solenoid may be quite strong, but the field has no associated electric potential. If the wire is ideal with no resistance, total electric field is zero inside it, so the induced electric field has to be always opposite to and of the same magnitude as the imposed electric field due to power source.

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