1. What is Capacitance with Dielectric?

The capacitance of a parallel plate capacitor increases when a dielectric material is inserted between the plates. The dielectric reduces the electric field and increases the capacitance by a factor equal to the relative permittivity (ε_r) of the material.

2. How Does the Calculator Work?

The calculator uses the capacitance equation:

Where:

• \( C \) — Capacitance (Farads)
• \( \epsilon_r \) — Relative permittivity of dielectric (dimensionless)
• \( \epsilon_0 \) — Vacuum permittivity (8.854 × 10^-12 F/m)
• \( A \) — Plate area (m²)
• \( d \) — Plate separation (m)

Explanation: The equation shows that capacitance increases with larger plate area, higher dielectric constant, and smaller plate separation.

3. Importance of Dielectric Materials

Details: Dielectrics are essential in capacitors as they increase capacitance, prevent arcing between plates, and allow for higher voltage operation. Different materials have different relative permittivity values.

4. Using the Calculator

Tips: Enter relative permittivity (≥1), plate area in m², and plate separation in m. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is relative permittivity?
A: It's the ratio of the permittivity of a material to the permittivity of vacuum, indicating how much the material increases capacitance compared to vacuum.

Q2: What are typical ε_r values?
A: Air ≈1, Paper ≈3.5, Glass ≈5-10, Water ≈80. Special ceramics can have ε_r > 1000.

Q3: Why does capacitance increase with dielectric?
A: The dielectric reduces the effective electric field between plates, allowing more charge to be stored at the same voltage.

Q4: What if my plates aren't parallel?
A: This equation is for parallel plates only. Other geometries require different formulas.

Q5: How does temperature affect capacitance?
A: Many dielectrics have ε_r that varies with temperature, which changes capacitance.