AC capacitors voltage rating is based on which voltage value?

The voltage rating of AC capacitors is based on the RMS (Root Mean Square) value. This is because the RMS value provides a way to express AC voltage in terms that are comparable to DC voltage, reflecting the effective voltage that would result in the same power delivery. In practical applications, the RMS voltage is crucial as it determines the capacitor's ability to withstand the continuous voltage applied over time without risk of breakdown or failure.

Choosing RMS as the voltage reference is crucial for ensuring that capacitors operate safely under typical AC conditions, where voltage levels can change constantly. The RMS value represents the equivalent DC voltage that would produce the same amount of heat in a resistive load, making it a standard measure for electrical equipment ratings. This is especially relevant for capacitors, as they must be able to handle the AC voltage without risk of dielectric failure or degradation.