Calculadora de Energia em Capacitor
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
U = ½·C·V²
About this calculator
This calculator determines the energy stored in a capacitor using the formula U = ½·C·V², where U is energy in joules, C is capacitance in farads, and V is voltage in volts. It allows quick calculation of the electrical energy accumulated in a capacitor given any two of the three parameters (capacitance, voltage, or energy). The result is displayed in joules, with scientific notation for very small or large values.
This tool is useful for physics and electrical engineering students who need to check exercises or projects involving energy storage in capacitors. It is also applicable to technicians and hobbyists working with electronic circuits, such as power supplies, camera flashes, or energy storage systems where capacitors serve as temporary reservoirs.
Important precautions: ensure consistent units (farads, volts). Typical capacitance values range from picofarads (10⁻¹² F) to millifarads (10⁻³ F). The voltage must not exceed the capacitor's rated voltage to avoid damage or explosion. Note that the formula assumes an ideal capacitor; real capacitors have dielectric losses and equivalent series resistance (ESR) that dissipate some energy.
Frequently asked questions
What does the result in joules mean?
Joules is the SI unit of energy. It indicates the amount of electrical work the capacitor can deliver to the circuit.
Can I use capacitance in microfarads and voltage in volts?
Yes, but you need to convert microfarads to farads: 1 µF = 10⁻⁶ F. The calculator accepts scientific notation; enter 1e-6 for 1 µF.
Does the calculator work for electrolytic capacitors?
Yes, the formula is general. However, electrolytic capacitors have higher tolerance and losses, so the actual value may differ slightly.
What is the difference between energy and power?
Energy (joules) is the capacity to do work; power (watts) is the rate of energy transfer. A capacitor stores energy, not power.
Can I use the calculator for supercapacitors?
Yes, supercapacitors also follow the same formula. They have high capacitance (farads) and low voltage, so the energy can be significant.