Anonymous
Anonymous asked in Science & MathematicsEngineering · 1 month ago

# Does size of positive electrode also determine the capacitance of a cap or only the negative electrode (which accumulated electrons)?

Update:

*accumulates

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The area in the formula for capacitance of parallel plates is that of the *overlap* between the two.  Any part of either plate that lies outside this overlap zone is ignored in the calculation.

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• not at all in my opinion

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• The capacitance of a capacitor is a function of the total area of both electrodes, the space or medium between them and the dielectric constant of that space or medium, not just one but both plates.

• 1 month agoReport

Yeah, it's absurd how many people here are referencing the simplification of electric field between two identically sized parallel plates to claim that if the assumptions of the formula are not met then the output is the same as if they are met.

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• The size of both capacitor plates affects the capacitance value.

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• Capacitance is directly proportional to the area of overlap of the two plates, regardless of polarity.  Making one plate larger without increasing the amount of overlap does nothing to the capacity.

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• Both electrodes accumulate charge.  The more charge that can be pushed onto the plates at a given voltage, the greater the capacitance.  It's the proximity of the opposite charge that allows more charge to be pushed onto each plate.  If there was no opposite plate, the electric repulsion of all the like charges would prevent any further charge from accumulating.  The closer we bring the opposite plate, the greater the attraction of the electric field from that plate, counteracting the repulsion of all the like charges on this plate, and the more charge can accumulate on this plate.  So lots of plate area with close proximity to the opposite plate is what gives great capacitance.

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• The smaller one in size determines the capacitance.

• billrussell42
Lv 7
1 month agoReport

plus some edge effects

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• The basic equation for capacitance of a parallel plate capacitor is capacitance= epsilon * area/ distance   The area of both plates is in the numerator. For other designs, the actual equations are  a little different.

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• The surface area matters, so yes

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