Calculator
Example Data Table
| Case | Input | Formula | Capacitance |
|---|---|---|---|
| Basic CV | 2.5 µC, 5 V | C = Q / V | 5.000000e-7 F |
| Differential CV | 0.8 µC, 2 V | C = dQ / dV | 4.000000e-7 F |
| Dielectric | εr 3.9, 10 cm², 100 nm | C = ε0εrA / d | 3.453133e-7 F |
Formula Used
Charge voltage: C = Q / V
Differential CV: C = dQ / dV
Dielectric: C = ε0 × εr × A / d
Energy: E = 0.5 × C × V²
Reactance: Xc = 1 / (2πfC)
How To Use This Calculator
Select the method first. Use charge voltage for simple capacitor tests. Use differential CV for curve based readings. Use dielectric geometry for plate structures. Enter matching units carefully. Add frequency for reactance. Add ESR for the RC time constant. Press calculate. Then download the report.
Capacitance From CV Guide
What This Calculator Does
This calculator estimates capacitance from charge and voltage data. It also supports differential CV readings. A third method uses dielectric geometry. These options help with lab checks, component tests, and early design work. The result is shown in farads. Extra values explain circuit behavior.
Why CV Data Matters
CV means charge versus voltage in this tool. It can also describe capacitance versus voltage curves. In many devices, capacitance changes with bias. Diodes, sensors, varactors, and oxide layers can show this effect. Differential capacitance helps when charge changes over a small voltage step.
Main Inputs
The basic method needs charge and voltage. The differential method needs dQ and dV. Geometry needs area, thickness, and relative permittivity. Frequency gives capacitive reactance. ESR gives the RC time constant. Series and parallel counts estimate a simple capacitor bank.
Understanding Results
Capacitance shows how much charge is stored per volt. Energy shows stored electrical energy. Reactance shows opposition to alternating current. Time constant shows charge speed with resistance. Density compares capacitance against area. Bank value adjusts the result for series and parallel groups.
Accuracy Notes
Use consistent units. Very small charges need careful instruments. Real parts include leakage, tolerance, temperature drift, and dielectric absorption. CV curve results can depend on sweep rate and bias history. For safety critical systems, verify results with rated components and proper test equipment.
FAQs
What is capacitance from CV?
It is capacitance found from charge and voltage data. The common formula is C = Q / V.
What does differential capacitance mean?
It uses a small charge change divided by a small voltage change. The formula is C = dQ / dV.
Can I use microcoulombs?
Yes. Select µC in the unit field. The calculator converts it to coulombs before calculating.
Why is frequency included?
Frequency is used to calculate capacitive reactance. This helps estimate AC circuit behavior.
What is ESR?
ESR means equivalent series resistance. It helps estimate the RC time constant with capacitance.
Can this calculate dielectric capacitance?
Yes. Enter area, thickness, and relative permittivity. Then select the dielectric geometry method.
Why is my result zero?
A required voltage, voltage change, or thickness may be zero. Check the selected mode and inputs.
Is this suitable for final engineering design?
Use it for estimates and checks. Final designs need datasheets, tolerances, safety margins, and testing.