|Where does the exact reversal occur in an alternating current circuit (where does the energy diminish completely and then turn the opposite way)?
The reversal of the current in an alternating current (AC) circuit occurs everywhere in the circuit at once. The whole current gradually slows to a stop and then heads backward. At the moment it comes to a complete stop, the electric power company isn't supplying any power at all and the circuit isn't consuming any. Because the power delivery pulses on and off in this manner, devices that operate on AC power are designed to store energy between reversals. Motors store their energy as rotational motion. Stereos store energy as separated electric charge in devices called capacitors, or as magnetic fields in devices called inductors.