Learn how capacitors store electrical energy and their applications in circuits
A capacitor is an electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by an insulating material called a dielectric.
Capacitance Formula:
$$C = \frac{Q}{V}$$
Where C is capacitance (farads), Q is charge (coulombs), and V is voltage (volts)
The energy stored in a capacitor is given by:
$$E = \frac{1}{2}CV^2$$
Where E is energy (joules), C is capacitance (farads), and V is voltage (volts)
Example:
A 100μF capacitor charged to 12V stores:
$$E = \frac{1}{2} \times 100 \times 10^{-6} \times 12^2 = 0.0072 \text J$$
When a capacitor charges through a resistor, the voltage follows an exponential curve:
$$V(t) = V_s(1 - e^{-t/RC})$$
The time constant τ (tau) = RC determines how fast the capacitor charges:
Electrolytic capacitors are polarized and must be connected correctly: