Calculator · Electrical Engineering
Capacitance Calculator
A capacitor stores charge in proportion to the voltage across it: Q = C·V. Give two of capacitance, charge and voltage; the third and the stored energy follow.
Inputs
Q is the charge on the plate at the + terminal of V. Signed values are allowed; C must be positive, so solving for C needs Q and V non-zero with the same sign. Zero charge and voltage are valid otherwise.
Results
Charge Q = C·V
1.2 mC
| Capacitance C | 100 µF |
|---|---|
| Charge Q | 1.2 mC |
| Voltage V | 12 V |
| Stored energy E = ½·C·V² | 7.2 mJ |
Explore in the Lab
Open this capacitor in the Capacitors & Transients Lab
The Lab holds C at the voltage V (V0 = Vf = V), so it carries the same charge and energy.
Technical reference
C = Q/V
Q = C·V, V = Q/C
E = ½·C·V² = Q²/(2C) = ½·Q·V
- C
- capacitance (> 0)[F]
- Q
- charge on the + plate[C]
- V
- voltage across the capacitor[V]
- E
- stored energy (≥ 0)[J]
Ideal linear capacitor: C does not depend on V.
Equal and opposite charges sit on the two plates; the net charge is zero.