Capacitor Voltage Divider Calculator

A capacitor voltage divider splits an AC voltage into a lower output voltage using two capacitors in series — unlike resistor dividers, capacitors divide voltage inversely based on their capacitance values. Enter your Input Voltage (Vin), then set values and units for Capacitor C1 and Capacitor C2 to get the Output Voltage (Vout), along with the voltage ratio and the output as a percentage of input.

V

The AC voltage applied to the divider circuit

First capacitor value (from input to output)

Second capacitor value (from output to ground)

Results

Output Voltage (Vout)

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Voltage Ratio (Vout/Vin)

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Percentage of Input

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Frequently Asked Questions

What is a capacitive voltage divider?

A capacitive voltage divider is a circuit that uses two capacitors to divide an AC voltage. The output voltage is a fraction of the input voltage, determined by the ratio of the capacitor values.

How does a capacitor voltage divider work?

In AC circuits, capacitors have reactance that varies with frequency. The voltage divides across the capacitors inversely proportional to their capacitance values - smaller capacitance drops more voltage.

What is the formula for capacitive voltage division?

The output voltage is calculated as: Vout = Vin × (C1 / (C1 + C2)). Note that the capacitor with lower capacitance drops more voltage across it.

Why doesn't a capacitive voltage divider work with DC?

Capacitors block DC current after initial charging, so no steady current flows through the circuit. Capacitive dividers only work with AC or changing voltages where capacitive reactance applies.

What are the applications of capacitive voltage dividers?

They are used in AC coupling circuits, high-voltage measurement probes, phase shift networks, and frequency-dependent voltage division where isolation from DC is required.

How do I choose capacitor values for my voltage divider?

Choose values based on your desired voltage ratio and frequency response. Consider the load impedance and ensure the capacitive reactance is appropriate for your operating frequency.

What happens if I swap C1 and C2 values?

Swapping the capacitor values will change the output voltage. The formula shows that larger C1 relative to C2 gives higher output voltage, while smaller C1 gives lower output voltage.

Are there any limitations to capacitive voltage dividers?

Yes, they are frequency-dependent, only work with AC signals, can introduce phase shifts, and the output impedance varies with frequency. They're also sensitive to load impedance.