I Parallel plate capacitor, charge imbalance VS charge redistribution

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In a parallel plate capacitor, charge imbalance occurs as one plate gains excess electrons while the other loses them, but the total charge remains conserved. When one plate is grounded, it can maintain neutrality through charge redistribution, allowing it to mirror the charge on the opposite plate without developing a net charge imbalance. This scenario is theoretically possible, as the grounded plate can reflect changes in the electric field without contributing to overall charge. The displacement current concept supports this, indicating that charge lost from one plate is gained by the other. Understanding these dynamics is crucial for analyzing capacitor behavior in practical circuits.
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Under normal circumstances both plates of a parallel plate capacitor develop a charge imbalance in each plate as the capacitor gets charged, the charges redistribute with one plate lacking electrons and the other plate having an excess of electrons, both plates together still can be though of as neutral because the total charge per both plates is conserved.


Is there a situation where this is not the case?

Like, for example, a parallel plate capacitor where one plate has a very good low resistance ground connection, now the other plate gets charged and it develops either an excess or lack of electrons , but the other plate only becomes polarized, that is the charges within the plate redistribute to form a surface charge to mirror the charges on the other plate but overall the plate itself stays neutral because for any lacking or excess charge , additional charge flows in or is sourced to the ground to let the plate be overall neutral so that it only has a charge redistribution but not a charge imbalance in it.

Is this practically possible and does it work in theory?


Similarly to how one shines a laser against a mirror and the laser is reflected but the mirror itself is not the source of the laser energy it just reflects it , similarly here one plate is actually "driven" to have an actual charge imbalance within it meanwhile the other plate simply is impacted by the E field and develops a charge redistribution to form a surface charge layer but the overall charge is neutral within the whole plate.
 
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FusionJim said:
Is this practically possible and does it work in theory?
Consider the displacement current. To charge a capacitor, what is lost from one side must be gained by the other.

When one side of a capacitor is connected to a low resistance ground, that defines a reference voltage, it plays no part in the charge distribution within the capacitor.

Changing the common mode voltage of the capacitor terminals suggests an external circuit is present, and that the unbalanced charges are being distributed on the outside of the capacitor's plates. If the charges are not balanced, then you need to identify the other components involved in the hypothetical circuit you are considering.

Consider the mid-voltage equipotential within a symmetrical parallel plate capacitor. One plate can be seen as a reflection of the other, with the polarity of the charge, and the voltage being reversed in the reflection. A perfect mirror is a perfect conductor, and an equipotential.
 
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