Capacitive Voltage Divider

Vout = Vin · C1 / (C1 + C2)

Quick answer

This calculator solves Vout = Vin × C1 / (C1 + C2) (Vout across C2) for Output Voltage. With Input Voltage 26.4 V, Top Capacitor 100 nF, Bottom Capacitor 0.22 µF, the result is 8.25 V. It solves in 4 directions, so you can enter the values you have and get the one you need.

Calculator

Output Voltage (V)
—

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.

Symbols and units

Symbol Meaning Default unit Accepted units
Vout Output Voltage V pV, nV, µV, mV, V, kV
Vin Input Voltage V pV, nV, µV, mV, V, kV
C1 Top Capacitor nF pF, nF, µF, mF, F
C2 Bottom Capacitor nF pF, nF, µF, mF, F

Step by step

  1. 1. What you know: Input Voltage 26.4 V, Top Capacitor 100 nF, Bottom Capacitor 0.22 µF
  2. 2. The relation: Vout = Vin × C1 / (C1 + C2) (Vout across C2)
  3. 3. Substitute: Vin = 26.4 V, C1 = 100 nF, C2 = 0.22 µF
  4. 4. Result: Output Voltage = 8.25 V

Worked examples

Minimum range

Given: Input Voltage 0.726 V, Top Capacitor 100 pF, Bottom Capacitor 0.22 nF

Result: Output Voltage = 0.2269 V

Low range

Given: Input Voltage 7.26 V, Top Capacitor 1 nF, Bottom Capacitor 2.2 nF

Result: Output Voltage = 2.269 V

Typical

Given: Input Voltage 26.4 V, Top Capacitor 100 nF, Bottom Capacitor 0.22 µF

Result: Output Voltage = 8.25 V

High range

Given: Input Voltage 0.506 kV, Top Capacitor 1 µF, Bottom Capacitor 2.2 µF

Result: Output Voltage = 158.1 V

Maximum range

Given: Input Voltage 5.06 kV, Top Capacitor 10 µF, Bottom Capacitor 22 µF

Result: Output Voltage = 1.581 kV

Solving for each variable

Solve for Output Voltage

Input Voltage 0.726 V, Top Capacitor 100 pF, Bottom Capacitor 0.22 nF → 0.2269 V

Solve for Input Voltage

Output Voltage 0.33 V, Top Capacitor 100 pF, Bottom Capacitor 0.22 nF → 1.056 V

Solve for Top Capacitor

Output Voltage 0.33 V, Input Voltage 0.726 V, Bottom Capacitor 0.22 nF → 0.1833 nF

Solve for Bottom Capacitor

Output Voltage 0.33 V, Input Voltage 0.726 V, Top Capacitor 100 pF → 120 pF

How Output Voltage changes with Input Voltage

Input Voltage (input) Output Voltage (result)
2.64 V 0.825 V
6.6 V 2.062 V
13.2 V 4.125 V
19.8 V 6.187 V
26.4 V 8.25 V
39.6 V 12.37 V
52.8 V 16.5 V
105.6 V 33 V
0.1848 kV 57.75 V
0.264 kV 82.5 V

The same result in other units

Unit Value
µV 8250000
mV 8250
V 8.25
kV 0.00825

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Frequently asked questions

How do you calculate Capacitive Voltage Divider?

Use Vout = Vin × C1 / (C1 + C2) (Vout across C2). With Input Voltage 26.4 V, Top Capacitor 100 nF, Bottom Capacitor 0.22 µF, Output Voltage works out to 8.25 V.

What is the formula for Capacitive Voltage Divider?

The formula is 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.

How do you find Input Voltage when you know the other values?

Rearrange for Input Voltage: with Output Voltage 0.33 V, Top Capacitor 100 pF, Bottom Capacitor 0.22 nF, Input Voltage is 1.056 V.

How do you find Top Capacitor when you know the other values?

Rearrange for Top Capacitor: with Output Voltage 0.33 V, Input Voltage 0.726 V, Bottom Capacitor 0.22 nF, Top Capacitor is 0.1833 nF.

What units does Capacitive Voltage Divider use?

Output Voltage is shown in µV, mV, V, kV. Values are held in SI base units internally, so you can mix prefixes without converting by hand.

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