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Relative Permittivity

Reference data and engineering information about relative permittivity for miscellaneous applications.

relativepermittivity

Overview

Engineering reference data for Relative Permittivity in miscellaneous.

Key Formulas

Unit Conversion

y=xky = x \cdot k

Multiply by conversion factor.

Linear Interpolation

y=y1+(xx1)(y2y1)x2x1y = y_1 + \frac{(x - x_1)(y_2 - y_1)}{x_2 - x_1}

Estimate between two known points.

Percentage

p=partwhole×100%p = \frac{\text{part}}{\text{whole}} \times 100\%

Part as fraction of whole.

Variables

SymbolDescriptionUnit
xxInput value
yyOutput value
kkConversion factor
94 rows
Relative Permittivity (Dielectric Constant) for Various Materials
Material
Relative Permittivity (εr)
Acetaldehyde (41°F)21.8
Acetic Acid (68°F)6.2
Acetic Acid (36°F)4.1
Acetone (77°F)20.7
Acetone (127°F)17.7
Acetone (32°F)1.0159
Acetyl Acetone (68°F)23.1
Acetyl Bromide (68°F)16.5
Acetyl Chloride (68°F)15.8
Air (Dry) (68°F)1.000536
Air, Liquid (-191 oC)1.4
Alumina9.3-11.5
Aluminum Bromide (212°F)3.4
Aluminum Fluoride2.2
Ammonia (-74°F)25
Ammonia (69°F)16.5
Aniline (68°F)7.3
Bakelite3.5-5.0
Benzene (68°F)2.3
Carbon dioxide (68°F)1.000921
Ceramic, MgNb2O621
Ceramic, ZnNb2O625
Ceramic, MgTa2O628
Ceramic, ZnTa2O638
Chloroform (68°F)4.8
Concrete4.5
Diamond5.5 - 10
Ebonite2.5 - 2.9
Epoxy Resin (Cast)3.6
Ethanol (25 oC, 77°F)24.3
Ethylene glycol37
Formamide (20 oC)84
Formica4.6 - 4.9
Furfural42
R12 Dichlorodifluoromethane (70°F)2.4
Glass3.7 - 10
Glass, Pyrex4.8
Glycerin, Liquid47-68
Glycerol (77°F)42.5
Granite7 - 9
Graphite10 - 15
Ice (-2 oC)3.2
Isoprene (77°F)2.1
Insulation of high voltage cables4.2
Insulation of telephone cables1.5
Marble8
Methanol (20 oC)33.6
Mica2.5 - 7
Mineral Oil (80°F)2.1
Mylar3.1
Neoprene6.7
Nylon4.0 - 5.0
Oil paper4
Paper2.3
Paper, impregnated5
Paper, waxed2.5
Paraffin oil2.2
Paraffin Wax2.1-2.5
Petroleum2.2
Phenolic resin8
Plexiglass3.2
Polyester Resin2.8 - 4.5
Polyethylene, XLPE2.2-2.4
Polyamide2.8
Polymide3.4
Polypropylene2.2
Polystyrene3
Porcelain5.0-7.0
Pyrex Glass4.3 - 5.0
Quartz4.5
Rubber3
Salt3.0 - 15.0
Sapphire8.9 - 11.1
Shellac3.5
Silica Sand2.5-3.5
Silicon11.0 - 12.0
Silicon dioxide3.9
Silicon oil2.2 - 2.8
Slate4
Sodium chloride5.6
Soft rubber2.5
Steatite6
Sulfur3.5
Sulfuric acid (20 oC)84
Polytetrafluoroethylene (PTFE)2
Teflon, PTFE2.1
Titanium dioxide86 - 173
Transformer oil, mineral2.2
Transformer oil, vegetable2.5
Turpentine2.2
Vacuum1
Vulcanized fibres2.5
Water4 - 88
Wood, Dry2 - 6

Source: engineeringtoolbox.com

Temperature Dependence

The relative permittivity of a material is not a constant and can vary significantly with temperature. This is especially true for polar materials like water. For example, water's permittivity is approximately *88 at 0°C (32°F), dropping to *80 at 20°C (68°F) and further decreasing to *55.3 at 100°C (212°F). When selecting a dielectric material for an application, its permittivity value must be considered at the operating temperature.

References