Soldering terminology

The dielectric constant, also known as dielectric number or permittivity (ε), is a measure of the electrical excitation of a dielectric (insulator) when voltage is applied to it. Its value is material-specific and should be as low as possible for soldering residues since nowadays assemblies are commonly soldered with RMA flux and packed in plastic without cleaning. It is defined as follows:

ε = D/E

D: dielectric flux density (C/m ² ), E : electric field strength (V/m).

The ε quotient of the dielectric constant of a material and the ε ₀ dielectric constant of air

ε _s = ε / ε ₀

is called relative or specific permittivity. For air this value is 1.