Capacitor Charge Calculator
Calculate charge on capacitor Q = C × V.
Enter Values
Fill in the fields and press Calculate to see instant results.
What is the Capacitor Charge Calculator?
The Capacitor Charge Calculator computes the electrical charge stored on a capacitor based on its capacitance and applied voltage. Charge is a fundamental concept in capacitor theory, determining how much electrical energy the capacitor stores and its ability to power circuits. Understanding capacitor charge is essential for power supply design, timing circuits, energy harvesting systems, and many electronic applications.
Formula
The charge stored on a capacitor is calculated using:
Where:
- Q = Charge (measured in coulombs, C)
- C = Capacitance (measured in farads, F)
- V = Voltage (measured in volts, V)
Note: 1 coulomb = 1 ampere × 1 second (As) - the charge passed by 1 amp of current in 1 second
How to Use
- Enter the Capacitance (C) in farads (F)
- Enter the Voltage (V) in volts (V)
- Click Calculate
- The calculator displays the Charge (Q) in coulombs (C)
Worked Example
Given:
- Capacitance (C) = 1,000 μF (0.001 F)
- Voltage (V) = 12 V
Calculation:
Q = C × V = 0.001 F × 12 V = 0.012 C (coulombs)
Or: Q = 12 millicoulombs (mC)
Interpretation: The capacitor stores 0.012 coulombs of charge at 12V
Real-World Applications
- Power Supply Smoothing: Capacitors store charge to smooth DC voltage ripples from rectifiers
- Flash Photography: Camera flash capacitors store high charge for instant energy delivery
- Energy Harvesting: Determine stored energy in capacitive energy storage systems
- Audio Coupling: AC coupling capacitors store charge for signal transmission between amplifier stages
- Motor Starting: Run capacitors store charge to create phase shift for motor operation
Capacitance Values (Common)
- Picofarad (pF): 10-12 F - Used in high-frequency circuits
- Nanofarad (nF): 10-9 F - Used in timing and filtering circuits
- Microfarad (μF): 10-6 F - Most common for general applications
- Millifarad (mF): 10-3 F - Used in power supplies and energy storage
- Farad (F): 1 F - Used in supercapacitors and backup power systems
Key Definitions
- Charge (Q): The amount of electrical charge stored, measured in coulombs (C)
- Coulomb (C): Unit of electrical charge; 1 C = charge transferred by 1 A of current in 1 s
- Capacitance (C): Ability to store electrical charge, measured in farads (F)
- Voltage (V): Electrical potential difference across capacitor plates
- Capacitor: Two-terminal device that stores electrical energy in an electric field
- Dielectric: Insulating material between capacitor plates that enhances charge storage
Frequently Asked Questions
What is the relationship between charge, capacitance, and voltage?
Charge is directly proportional to both capacitance and voltage: Q = C × V. Doubling voltage doubles stored charge; doubling capacitance doubles stored charge.
How much energy does a charged capacitor store?
Energy stored: E = 0.5 × C × V² (in joules). A higher voltage significantly increases stored energy (quadratic relationship). A 1F capacitor at 100V stores 5,000 joules.
What is a coulomb?
A coulomb is the unit of electrical charge. One coulomb is the charge transferred by 1 ampere of current flowing for 1 second. One coulomb = 6.242 × 10¹⁸ electrons.
What happens when voltage increases across a capacitor?
Increasing voltage increases the charge stored proportionally. Higher voltage requires more charge to move to the capacitor plates, with more stored electrical energy.
What is the maximum charge a capacitor can store?
Maximum charge depends on capacitance and breakdown voltage rating. Exceeding the breakdown voltage causes dielectric failure. Always operate within voltage rating for safety and reliability.
How do supercapacitors differ from regular capacitors?
Supercapacitors have much higher capacitance (1-3000 F) due to special construction using double-layer capacitance. They store more charge and energy than conventional capacitors but operate at lower voltages.