Calculate relative permittivity (εᵣ) from capacitance, ideal parallel-plate geometry, electric-force measurements, or absolute permittivity.
Dielectric Constant Formula
The following formula is used to calculate a dielectric constant.
- Where k is the dielectric constant
- ε is the absolute permittivity of the substance
- ε0 is vacuum permittivity: 8.8541878188(14)×10−12 F⋅m−1 (2022 CODATA recommended value).
To calculate a dielectric constant, divide the permittivity of the substance by the permittivity of a vacuum.
For the same capacitor geometry, full dielectric filling and measurement conditions, k = C/C₀. The ideal parallel-plate mode uses k = Cd/(ε₀A) and neglects fringing. Force mode uses k = F₀/F for unchanged free charges and separation in a homogeneous linear medium. The reported relative permittivity is dimensionless; real materials vary with frequency and temperature.
Dielectric Constant Definition
A dielectric constant is a measure of the permittivity of a substance compared to the permittivity of a vacuum.
Dielectric Constant Example
How to calculate a dielectric constant?
- First, determine the permittivity of the substance.
Measure or calculate the permittivity of the substance.
- Next, determine the permittivity of the vacuum.
The 2022 CODATA recommended value is (8.8541878188(14)×10−12 F⋅m−1).
- Finally, calculate the dielectric constant.
Calculate the dielectric constant using the formula above.
FAQ
In simple terms, a dielectric constant is a measure of the relative permittivity of an object when compared to a vacuum.
Permittivity is a measure of how much polarizability a given dielectric has. In other words, how much energy it can store when exposed to an electric field.
A dielectric is a substance or object that acts as an electrical insulator. When exposed to an electric field it becomes polarized, thus storing energy.
