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Capacitors in series
Intermediate
Reciprocals add.
1/C = 1/C₁+1/C₂Series capacitors store the same charge and their voltages add: 1/C = Σ1/Cᵢ, so the total is smaller than any.
Two 4 μF: 2 μF.
Opposite of resistors.
In more detail
In series, capacitors share the same charge, and the equivalent capacitance satisfies 1/C = Σ(1/Ci). The total is smaller than any individual capacitor.
Real-world uses
- Series capacitors are used when a high voltage must be shared among components.
- Circuit design uses series combinations to reduce capacitance.
- Engineers arrange capacitors in series to achieve a lower capacitance and a higher voltage rating for a circuit.
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Frequently asked questions
Why is the total smaller?
Because the separation effectively increases, reducing capacitance.
Do series capacitors share voltage?
Yes, the voltage divides in inverse proportion to capacitance.
Why does the total capacitance get smaller?
Adding capacitors in series increases the total separation, and the charge is the same on each, so the combined capacitance falls.
Related topics in Electrostatics
Potential energy of charges · Capacitor · Parallel-plate capacitor · Capacitors in parallel · Energy in a capacitor · Energy density of field