Study capacitor plate behavior with interactive calculations. Estimate field strength, energy, charge, and breakdown margins. Simple inputs, responsive layout, exports, graphing, examples, and guidance.
| Material | Voltage | Separation | Area | εr | Field | Capacitance | Charge |
|---|---|---|---|---|---|---|---|
| Air | 100 V | 1 mm | 100 cm² | 1.0006 | 1.000000e+5 V/m | 8.859500e-11 F | 8.859500e-9 C |
| Glass | 250 V | 2 mm | 150 cm² | 5 | 1.250000e+5 V/m | 3.320320e-10 F | 8.300800e-8 C |
| Mica | 500 V | 0.5 mm | 50 cm² | 6 | 1.000000e+6 V/m | 5.312520e-10 F | 2.656260e-7 C |
| Teflon | 1.2 kV | 3 mm | 200 cm² | 2.1 | 4.000000e+5 V/m | 1.239590e-10 F | 1.487508e-7 C |
Absolute electric field: E = |V| / d
Adjusted field: Eadj = E × fringing factor
Permittivity: ε = ε0 × εr
Capacitance: C = (εA / d) × fringing factor
Charge: Q = C × V
Surface charge density: σ = ε × Eadj
Energy density: u = ½ εEadj2
Stored energy: U = ½ CV2
Electrostatic pressure: P = ½ εEadj2
Safety factor: dielectric strength / adjusted field
The calculator uses ε0 = 8.854187817 × 10-12 F/m.
This calculator estimates the electric field between two capacitor plates. It also finds capacitance, charge, energy density, stored energy, and electrostatic pressure. These values help you study how a parallel plate capacitor behaves. The tool is useful for physics work, electronics practice, and lab preparation.
Plate separation strongly affects field strength. When voltage stays fixed, a smaller gap produces a stronger field. That means the dielectric material experiences more stress. If the field becomes too large, insulation may fail. This is why breakdown checks matter in practical capacitor design.
A dielectric changes the effective permittivity between plates. Higher relative permittivity increases capacitance. More capacitance allows more charge storage at the same applied voltage. Different materials also have different dielectric strength limits. A material may store charge well but still break down under a strong field.
Plate area increases capacitance. Larger plates store more charge because they provide more surface for electric flux. In the ideal parallel plate model, area does not directly change the field for a fixed voltage and spacing. However, area still changes the total charge and stored energy.
Real capacitor fields are not perfectly uniform near the plate edges. This edge spreading is called fringing. The fringing factor gives a simple correction for more realistic estimates. A value of 1 keeps the ideal model. Larger values can represent stronger edge effects in approximate studies.
The graph shows how electric field changes when spacing changes. As distance grows, the field drops. As distance shrinks, the field rises quickly. Comparing the curve with dielectric strength helps you identify safer operating regions for a chosen material and voltage.
It is the voltage difference divided by the plate separation. In an ideal parallel plate capacitor, the field is nearly uniform in the space between the plates.
In the ideal model, no. Field strength depends mainly on voltage and spacing. Plate area changes capacitance, charge storage, and total stored energy instead.
Relative permittivity changes the material permittivity. That directly affects capacitance, surface charge density, and energy calculations. It is essential when a dielectric fills the gap.
Dielectric strength is the maximum field a material can withstand before electrical breakdown starts. The calculator compares your field estimate against this limit for a safety check.
It adds a simple correction for edge effects. Real fields spread near plate boundaries. A fringing factor above 1 gives a less ideal estimate.
Stored energy depends on one half times capacitance times voltage squared. Because voltage is squared, the energy remains positive even if voltage polarity changes.
You can enter voltage in V, kV, or mV. Distance supports m, cm, mm, and µm. Area supports m², cm², and mm².
With voltage fixed, the ideal electric field doubles. Capacitance also increases because the plates are closer. Breakdown risk rises if the dielectric limit is approached.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.