Enter Series Capacitor Values
Use comma, space, or semicolon separated values.
Formula Used
For capacitors connected in series, the same charge flows through each capacitor.
Equivalent capacitance:
1 / Ceq = 1 / C1 + 1 / C2 + ... + 1 / Cn
Charge:
Q = Ceq × Vtotal
Voltage across each capacitor:
Vi = Q / Ci
Energy stored:
Ei = 0.5 × Ci × Vi2
How to Use This Calculator
- Enter at least two capacitor values.
- Select the matching capacitance unit.
- Enter the total voltage across the series string.
- Add voltage ratings if you want safety margin checks.
- Enter tolerance to estimate the worst high voltage case.
- Press the calculate button.
- Review the result table and chart.
- Download the CSV or PDF report if needed.
Example Data Table
| Example | C1 | C2 | C3 | Total Voltage | Expected Use |
|---|---|---|---|---|---|
| Small signal divider | 10 µF | 22 µF | 47 µF | 24 V | Voltage sharing study |
| High voltage stack | 1 µF | 1 µF | 1 µF | 300 V | Equal voltage split |
| Unequal bank | 4.7 µF | 10 µF | 22 µF | 48 V | Stress comparison |
Understanding Capacitors in Series
What This Calculator Does
Capacitors in series do not divide voltage equally unless their capacitance values are equal. The same charge is stored on each capacitor. The smaller capacitor receives the larger voltage. This calculator shows that behavior clearly. It finds equivalent capacitance, charge, voltage share, energy, and safety margin. It also estimates a worst high voltage case using tolerance.
Why Voltage Sharing Matters
Series capacitors are often used when one capacitor cannot handle the full voltage. Designers may place several capacitors together to increase the total voltage withstand level. This can work well, but only with care. Real parts have leakage current. They also have tolerance and aging effects. These differences can push extra voltage onto one capacitor. That part may fail first.
Equivalent Capacitance
The equivalent capacitance of a series string is always smaller than the smallest capacitor. This is different from parallel capacitors. In a series path, each capacitor limits charge movement. The total capacitance therefore drops. A lower equivalent value means less charge for the same applied voltage.
Using Tolerance
Tolerance is important in practical electrical design. A capacitor marked as ten microfarads may be higher or lower. The calculator uses tolerance to estimate the highest possible voltage across each part. This is useful before building a circuit. It does not replace manufacturer data. It gives a practical warning for quick design checks.
Safety Notes
High voltage capacitor banks can be dangerous. Stored energy may remain after power is removed. Always use discharge paths. Use balancing resistors when voltage sharing must stay controlled. Choose rated parts with enough margin. Check ripple current, temperature, dielectric type, and surge limits. Good design keeps every capacitor below its safe operating range.
FAQs
1. Do series capacitors share voltage equally?
No. Equal voltage sharing happens only when capacitance values are equal and leakage effects are similar. Unequal capacitance causes unequal voltage distribution.
2. Which capacitor gets the highest voltage?
The smallest capacitor gets the highest voltage in an ideal series connection because voltage is inversely related to capacitance.
3. Why is equivalent capacitance lower in series?
Each capacitor restricts charge movement in the same path. The combined effect lowers the total capacitance below the smallest individual value.
4. Should I use balancing resistors?
Yes, especially in high voltage circuits. Balancing resistors reduce voltage mismatch caused by leakage current differences and aging.
5. Can I use different capacitor values in series?
Yes, but the voltage split becomes uneven. Always check voltage stress on every capacitor before using mixed values.
6. What does tolerance do in this calculator?
Tolerance estimates a worst high voltage condition. It helps show how value variation can increase stress on one capacitor.
7. Is the stored energy the same in every capacitor?
No. The charge is the same, but energy depends on capacitance and voltage. Different values store different energy amounts.
8. Can this calculator replace datasheet checks?
No. It supports early design checks. Always verify voltage rating, ripple current, leakage, temperature, and surge limits from datasheets.