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Capacitors in parallel
Intermediate
Capacitances add.
Key relation
C = C₁+C₂Parallel capacitors share the same voltage and charges add: C = ΣCᵢ.
Worked example
4 μF + 6 μF = 10 μF.
Common mistake
Bigger area equivalently.
In more detail
In parallel, capacitors share the same voltage, and their capacitances add, C = ΣCi. The total capacitance is larger than any individual one.
Real-world uses
- Parallel capacitors increase total charge storage in power supplies.
- Filter networks use parallel capacitors to change cut-off frequencies.
- Electronic designers add capacitors in parallel to increase the capacitance for smoothing power supplies.
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Frequently asked questions
Why do they add?
Because the total plate area effectively increases with parallel connections.
Do parallel capacitors share the same charge?
No, each has its own charge proportional to its capacitance at the same voltage.
Why do capacitances add in parallel?
The plates are at the same voltage, so the total charge is the sum of the charges on each capacitor.
Related topics in Electrostatics
Capacitor · Parallel-plate capacitor · Capacitors in series · Energy in a capacitor · Energy density of field · Dielectrics