Dielectric permittivity, also known as dielectric
constant, is a property of insulating materials that characterises their interaction with an electric
field. It is relevant because the Epsilon sensor responds to capacitance and capacitance depends on dielectric
permittivity. The reason we emphasise dielectric permittivity rather than capacitance is calibration.
permittivity is a material property that can be used for calibration, whereas capacitance is a device
property for which no calibration standards are available. The common symbol used for dielectric permittivity
is the Greek letter Epsilon (ε) and this is where the Epsilon got its name from.
The dielectric permittivity of some common materials
is listed in the table below.