1. What is Relative Permittivity?

Relative permittivity (εᵣ), also known as dielectric constant, is a measure of how much a dielectric material reduces the electric field compared to a vacuum. It represents how well a material can store electrical energy in an electric field.

2. How Does the Calculator Work?

The calculator uses the relative permittivity formula:

Where:

• \( \varepsilon_r \) — Relative permittivity (unitless)
• \( C \) — Capacitance with dielectric (F)
• \( C_0 \) — Capacitance without dielectric (F)

Explanation: The formula compares the capacitance of a capacitor with a dielectric material to the capacitance of the same capacitor with vacuum (or air) between its plates.

3. Importance of Relative Permittivity

Details: Relative permittivity is a crucial parameter in capacitor design, insulation materials, and electromagnetic applications. It determines how much electric field is reduced when a dielectric material is present between charged plates.

4. Using the Calculator

Tips: Enter both capacitance values in farads (F). Ensure both values are positive and that the capacitance with dielectric is greater than the capacitance without dielectric for meaningful results.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of typical relative permittivity values?
A: For most common dielectric materials, relative permittivity ranges from about 2 to 8. Water has a high relative permittivity of about 80 at room temperature.

Q2: Can relative permittivity be less than 1?
A: No, relative permittivity is always greater than or equal to 1. A value of 1 represents vacuum, and all materials have εᵣ ≥ 1.

Q3: How does temperature affect relative permittivity?
A: Relative permittivity generally decreases with increasing temperature as molecular alignment with the electric field becomes more difficult.

Q4: What's the difference between relative permittivity and absolute permittivity?
A: Absolute permittivity (ε) has units (F/m), while relative permittivity (εᵣ) is dimensionless. They're related by ε = εᵣ × ε₀, where ε₀ is the vacuum permittivity.

Q5: Why is relative permittivity important in capacitor design?
A: Higher relative permittivity allows for smaller capacitors with the same capacitance value, as it increases the charge storage capacity for a given size and voltage.