Series Capacitor Calculator

Source Voltage (V)

Frequency (Hz)

Tolerance (%)

Leakage / Derating Factor

Temperature Coefficient (ppm/°C)

Temperature Change (°C)

Capacitor Values
One value per line. Example: 10

Units
One unit per line: F, mF, uF, nF, pF

Rated Voltages (V)
One voltage per line. Example: 50

Interactive Plotly Graph

Example Data Table

Scenario	Capacitors	Supply Voltage	Equivalent Capacitance	Main Insight
Small lab network	10 µF, 22 µF, 47 µF	24 V	6.459 µF	The smallest capacitor receives the largest voltage share.
High voltage stack	4.7 nF, 4.7 nF, 4.7 nF	900 V	1.567 nF	Equal capacitances split voltage nearly evenly.
Mixed tolerance chain	100 nF, 220 nF, 330 nF	120 V	56.897 nF	Tolerance changes the effective total noticeably.

Formula Used

1) Equivalent capacitance in series

\[ \frac{1}{C_{eq}} = \frac{1}{C_1} + \frac{1}{C_2} + \frac{1}{C_3} + \dots + \frac{1}{C_n} \]

2) Charge stored in a series chain

\[ Q = C_{eq} \times V \]

3) Voltage across each capacitor

\[ V_i = \frac{Q}{C_i} \]

4) Energy in each capacitor

\[ E_i = \frac{1}{2} C_i V_i^2 \]

5) Capacitive reactance

\[ X_C = \frac{1}{2\pi f C} \]

This calculator also estimates minimum and maximum equivalent capacitance using tolerance and a simple temperature coefficient adjustment.

How to Use This Calculator

Enter the source voltage and operating frequency.
Type one capacitor value per line.
Provide matching units for each capacitor line.
Optionally enter each rated voltage for safety checking.
Set tolerance, leakage factor, and temperature assumptions.
Press the calculate button to show results above the form.
Review equivalent capacitance, voltage distribution, energy, and reactance.
Use the graph and export buttons for reporting.

Frequently Asked Questions

1) What happens to capacitance in a series connection?

The equivalent capacitance becomes smaller than the smallest individual capacitor. Series connections reduce total capacitance because each capacitor shares the same charge.

2) Why does the smallest capacitor get the highest voltage?

In series, every capacitor carries the same charge. Since voltage equals charge divided by capacitance, a smaller capacitance produces a larger voltage drop.

3) Can I add different capacitor values in series?

Yes, but voltage division becomes uneven. Mixed values can overstress the smallest capacitor, especially in high-voltage designs without balancing resistors.

4) Why is rated voltage important here?

Each capacitor must withstand its own voltage share. If one capacitor exceeds its rating, breakdown, leakage, overheating, or failure can occur.

5) What is capacitive reactance in this calculator?

Capacitive reactance shows AC opposition at a chosen frequency. Lower reactance means the series network allows AC current more easily.

6) Does tolerance affect equivalent capacitance?

Yes. Real capacitors vary from their nominal values. Tolerance shifts total capacitance and changes the predicted voltage distribution across the chain.

7) When are balancing resistors useful?

They help equalize voltage across capacitors, especially in high-voltage stacks, mixed-value networks, or components with leakage differences.

8) Can this calculator replace laboratory verification?

No. It provides strong estimates, but final designs should be validated with measured capacitance, leakage, temperature behavior, and safety margins.