Equations

\dfrac{1}{C_{eq}}=\dfrac{1}{C_1}+\dfrac{1}{C_2}+\cdots+\dfrac{1}{C_n}

Q=C_{eq}V

E=\dfrac{1}{2}C_{eq}V^2

Electrical analysis

Equivalent capacitance59.977 nF

Total charge719.722 nC

Stored energy4.318 µJ

Minimum Equivalent capacitance53.979 nF

Maximum Equivalent capacitance65.974 nF

Worst-case equivalent capacitance when each capacitor has a 10% tolerance.

Per-capacitor voltage and energySmallest series capacitor sees the most voltage

CapacitorVoltageVoltage shareChargeEnergy

C1 · 100 nF7.197 V59.977%719.722 nC2.59 µJ

C2 · 220 nF3.271 V27.262%719.722 nC1.177 µJ

C3 · 470 nF1.531 V12.761%719.722 nC551.063 nJ

One-capacitor tuning assistant

Enter the desired equivalent capacitance. The assistant finds the exact and nearest E-series value for one added capacitor.

Target capacitance

Current error-94.002%

Add in parallel940.023 nF

Practical value (E24)910 nF

Expected equivalent969.977 nF

Results assume ideal, initially uncharged capacitors at a DC voltage. Check voltage rating, dielectric DC-bias loss, polarity, leakage, ESR, temperature, balance resistors and fault energy before release.

Network guide

Combine capacitors without losing voltage margin

Parallel capacitors increase charge storage; series capacitors reduce equivalent capacitance but can divide a high voltage. Nominal capacitance is not enough: check the voltage actually carried by every part.

Method and assumptions

In parallel, capacitances add and every capacitor sees the applied voltage. In series, the inverse of the equivalent capacitance is the sum of inverses; charge is the same in every capacitor and voltage divides inversely with capacitance. The tool also shows Q = C·V and E = ½·C·V².

Inputs to verify

Topology and applied voltage

Choose the connection actually present on the PCB. In series, identify the smallest capacitor: in the ideal model it receives the largest voltage share. In parallel, every part must withstand the full applied voltage.

Effective capacitance and tolerance

Use capacitance available at the intended voltage, temperature, and age. MLCCs can lose substantial capacitance under DC bias; also check leakage variation in series strings.

Recommended workflow

1Enter the values and the maximum voltage the network can actually see.
2Compare equivalent capacitance, charge, and energy with the functional requirement.
3Check each capacitor’s voltage, tolerance, derating, and balancing before selecting the combination.

Checkable example

With 1 µF and 2 µF at 12 V, the series connection gives 0.667 µF, 8 µC, and 48 µJ. Ideal voltages are 8 V across 1 µF and 4 V across 2 µF. In parallel, the network is 3 µF and stores 216 µJ; each capacitor sees 12 V.

Limits to keep in mind

The model is ideal and static. It does not simulate ESR/ESL, inrush current, dielectric absorption, leakage, or initial charge. These effects can strongly unbalance a series string or change high-frequency behaviour.

Frequently asked questions

Does voltage always split equally in series?

No. It is equal only for effectively equal capacitances in the ideal model. Tolerance, leakage, DC bias, and charge history move the midpoint; balance resistors or a dedicated analysis may be needed.

Why put multiple capacitors in parallel?

It can obtain a precise capacitance, share ripple current, or improve frequency response with complementary technologies. Then check ESR, ESL, ripple current, and voltage rating for every part.

References to consult

Method references: Q = C·V, electrostatic energy E = ½·C·V², IEC 60063 preferred numbers, and the datasheet of the selected capacitors.

Original educational content, reviewed for technical clarity on 20 August 2026. Always verify datasheets, applicable standards, and your design before power-up or manufacture.