Capacitance and inductance
Capacitors in series
- where
- total capacitance (F)
- individual capacitances (F)
Explain this equation
Works out the total capacitance of two capacitors in series. Used when stacking capacitors.
Cₜ is the combined capacitance. C₁ and C₂ are the two capacitors in series, carrying the same charge.
In series the same charge sits on each capacitor and their voltages add, so the combination holds less charge per volt. The reciprocals add, which for two capacitors gives product over sum.
Sense check: 100 µF and 200 µF in series give about 66.7 µF. Two equal capacitors give half of one. The answer is always below the smaller one.
Watch out: unequal capacitors do not share voltage equally; the smaller one takes more. Leakage makes real sharing uncertain too.
Two series capacitors have a total capacitance smaller than either capacitor. Product over sum gives the two-component result.
Voltage sharing depends on capacitance and practical leakage; putting capacitors in series does not automatically ensure safe voltage sharing.
Enter your values to see the result.
Common mistake
Assuming equal voltage across unequal capacitors.
Limits
Two ideal capacitors in series.
Sources
The tools calculate the displayed equation. They do not automatically choose cable sizes, approve installations, supply current regulatory tables, certify equipment or replace inspection and testing.