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What exactly creates the potential difference between the terminals of an AC source? In DC, an electrochemical cell causes charges to be moved within the cell from one electrode to the other and this work done on it is stored as its potential energy

I know that the basic principle of an alternating source of current is the changing magnetic flux linked with a conducting coil that is being rotated in the field. So what creates the potential difference in the circuit. Essential what part of the coil represents the analogous positive and negative terminals in DC circuits.

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    $\begingroup$ Is this just asking how an AC generator works? Have you attempted to research this, and if so can you give us some idea what specific aspects of it are unclear? $\endgroup$
    – John Rennie
    Commented Aug 9, 2016 at 13:44
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    $\begingroup$ Back at the power plant, a changing magnetic field induces an electric field in a coil of wire. That electric field drives motion of electrons, which is a current. That current is representative of an establishment of a potential difference $\endgroup$
    – Jim
    Commented Aug 9, 2016 at 13:45
  • $\begingroup$ @John Rennie In a DC source, there is a positive and negative terminal for a cell. What is the equivalent in an AC source. Which part of the coil acts as a positive terminal and which the negative. $\endgroup$
    – Sharpfawkes
    Commented Aug 9, 2016 at 14:59
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    $\begingroup$ @LeroyJD , do a bit of research on electromagnetic induction, as shown in the following link: en.wikipedia.org/wiki/Electromagnetic_induction $\endgroup$
    – David White
    Commented Aug 9, 2016 at 15:36
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    $\begingroup$ I'm voting to close this question as off-topic because of insufficient research effort. $\endgroup$
    – sammy gerbil
    Commented Aug 9, 2016 at 18:35

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Perhaps I understand what are you troubled about. You are right that a changing magnetic field induces in a coil a flux of electrons.

As long as the coil has open ends the amount of fre electrons is small and this amount will be moved to the one end of the coil and the inductance process stops. After the magnetic flux changes its direction the same amount of free available electrons will be moved to the opposite direction.

If the circuit isclosed a max bigger amount of free electrons is availible from the closed circuit and the electrons allong all wires will be moved nearly at the same time. This is because the change in electric potential in the generator changes along the wire with the speed of light (or at last very fast) and all the free electrons moving at once (but the drift velocity is comparing to the signal velocity very slow).

To say it short, a changing magnetic flux induces in a coil the movement of all the free electrons along of the circuit with a signal velocity of approx. the velocity of light. So every change in magnetic flux at once moves all the free electrons in the circuit and this with the frequency of 50 or 60 Hz.

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