Components
Capacitance
Capacitance is the ability of a component to store charge for a given voltage: C = Q ÷ V. The energy stored in the electric field is E = ½ × C × V². Because energy depends on the square of the voltage, doubling the voltage quadruples the stored energy, which is why capacitors can remain hazardous after the supply is removed.
Capacitance
C = Q ÷ V; E = ½ × C × V²
Variables and units
| Symbol | Quantity | Unit |
|---|---|---|
| C | Capacitance | F |
| Q | Stored charge | C |
| V | Voltage across the capacitor | V |
| E | Stored energy | J |
Conditions of application
Ideal capacitance with negligible leakage and equivalent series resistance. The energy formula gives the energy stored at a given voltage, not the energy delivered to a load.
Worked example
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