Dissipation factor

Electrical potential energy is dissipated in all dielectric materials, usually in the form of heat.

In a capacitor made of a dielectric placed between conductors, the typical lumped element model includes a lossless ideal capacitor in series with a resistor termed the equivalent series resistance (ESR) as shown below.

The ESR is a derived quantity with physical origins in both the dielectric's conduction electrons and dipole relaxation phenomena.

In dielectric only one of either the conduction electrons or the dipole relaxation typically dominates loss.

This gives rise to the parameter known as the loss tangent tan δ where Alternatively,

will vary depending on the dielectric material and the frequency of the electrical signals.

In low dielectric constant (low-κ), temperature compensating ceramics,

is usually an indication of quality capacitors when comparing similar dielectric material.

A real capacitor has a lumped element model of a lossless ideal capacitor in series with an equivalent series resistance (ESR). The loss tangent is defined by the angle between the capacitor's impedance vector and the negative reactive axis.