What is the formula for Capacitive Voltage Divider?

The Capacitive Voltage Divider formula is Vout = Vin × C1 / (C1 + C2) (Vout across C2), where Vout—Voltage across C2 (V); Vin—Total applied voltage (V); C1—Top (series) capacitor (F); C2—Bottom capacitor across the output (F).

Capacitive Voltage Divider

Q: How do you calculate Capacitive Voltage Divider?

Use the formula Vout = Vin × C1 / (C1 + C2) (Vout across C2). Two capacitors in series across an AC source divide the voltage in inverse proportion to their capacitances—the smaller capacitor drops the larger share. Enter the values you know in the calculator above and it solves for the remaining variable.

Vout = Vin · C1 / (C1 + C2)

Calculator

Output Voltage

Input Voltage

Top Capacitor

Bottom Capacitor

Result

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Formula

Vout = Vin × C1 / (C1 + C2) (Vout across C2)

Description

Two capacitors in series across an AC source divide the voltage in inverse proportion to their capacitances—the smaller capacitor drops the larger share. The voltage across the bottom capacitor is the input times the ratio of the top capacitor to the total. Capacitive dividers are used in high-voltage measurement, level shifting, and as the feedback network in Colpitts oscillators.

Variables

Vout — Voltage across C2 (V)
Vin — Total applied voltage (V)
C1 — Top (series) capacitor (F)
C2 — Bottom capacitor across the output (F)

Practical Notes

Unlike resistive dividers, this works only for AC (or transients)—at DC the capacitors block current and the division depends on leakage. Capacitive dividers draw almost no power, which suits high-voltage sensing.

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