Capacitive voltage transformers are used for AC voltage division.

Capacitive AC voltage division is similar to resistive voltage division. The difference is that capacitive voltage dividers divide voltage based on the capacitance impedance value, while resistive voltage dividers divide voltage based on the resistance value. The capacitance value is related to frequency, and the lower the frequency, the greater the capacitance. The resistance value is independent of frequency.

Therefore, capacitive voltage divider requires the measured signal to be AC power, and the frequency of AC power should not be too low or too high. Because too low a frequency leads to excessive capacitance and unstable voltage division, while too high a frequency leads to insufficient capacitance and excessive current flow. On the one hand, it affects the tested circuit, and on the other hand, it places high demands on the charging current of the capacitor.

The similarity between capacitive voltage divider and resistive voltage divider is that both do not have electrical isolation. Therefore, capacitive voltage transformers usually also pass through electromagnetic transformers to isolate the voltage on the primary and secondary sides after voltage divider.