Calculation
1/Ctotal = 1/C1 + 1/C2 (+ 1/C3)
Series-connected capacitors carry the same charge; the reciprocals of the capacitances add.
Busch 2006, Abschnitt 1.3.3, Gl. (1.46)
Capacitors in series
Series-connected capacitors carry the same charge; the reciprocals of the capacitances add.
MINTSI
02
Result
Select a target and calculate.
Understand the inputs
- Capacitance C1 — First capacitor in the series chain.
- Capacitance C2 — Second capacitor in the series chain.
- Capacitance C3 (optional) — Third capacitor; set to 0 if only two capacitors are present.
- Total capacitance Ctotal — Capacitance of the complete series chain; always smaller than the smallest individual capacitance.
Example
100 µF and 220 µF in series give 68.75 µF.
Assumptions and limits
Ideal, lossless capacitors with no leakage or ESR; uneven voltage sharing at strongly differing capacitances should be checked separately.
Understand Capacitors in series
This calculator determines the total capacitance of two or three capacitors connected in series, complementing the existing single parallel-plate capacitor calculation with the multi-component series rule.
What does this quantity describe?
Series-connected capacitors carry the same charge Q; since U=Q/C, partial voltages add to the total voltage, giving 1/Ctotal=1/C1+1/C2(+1/C3).
Formula and variables
1/Ctotal = 1/C1 + 1/C2 (+ 1/C3)
1/Ctotal = 1/C1 + 1/C2 (+ 1/C3)
| Symbol / input | Meaning |
|---|---|
| Capacitance C1 | First capacitor in the series chain. |
| Capacitance C2 | Second capacitor in the series chain. |
| Capacitance C3 (optional) | Third capacitor; set to 0 if only two capacitors are present. |
| Total capacitance Ctotal | Capacitance of the complete series chain; always smaller than the smallest individual capacitance. |
Choose the inputs correctly
C1 and C2 are the capacitances of the series-connected capacitors. C3 stays at 0 if only two capacitors are present.
How to use the calculator
Take capacitance values from component markings or datasheets and enter them in the chosen unit.
Worked example
100 µF and 220 µF in series give Ctotal=100·220/(100+220)=68.75 µF.
Understand the result and units
Ctotal is always smaller than the smallest individual capacitance; a very small third capacitance dominates the result.
All capacitances are entered in the same or convertible units (F, mF, µF, nF, pF).
Typical applications
Creating non-standard capacitance values from available components and estimating equivalent capacitance in series arrangements.
Assumptions, limits and common mistakes
Ideal, lossless capacitors with no leakage or ESR. At strongly differing capacitances, voltage sharing becomes uneven and must be checked separately.
Common mistake: Do not confuse this reciprocal-sum rule with the direct-sum parallel rule; structurally it mirrors the resistor series-of-reciprocals pattern.
Frequently asked questions
What is “Capacitors in series” used for?
Creating non-standard capacitance values from available components and estimating equivalent capacitance in series arrangements.
Where do the input values come from?
C1 and C2 are the capacitances of the series-connected capacitors. C3 stays at 0 if only two capacitors are present.
What does the result not cover?
Ideal, lossless capacitors with no leakage or ESR. At strongly differing capacitances, voltage sharing becomes uneven and must be checked separately.