page_title: Capacitor types
section_title: Series-equivalent circuit
hierarchical_section_title: Capacitor types / Electrical characteristics / Series-equivalent circuit
caption_attribution_description: English: Series-equivalent circuit model of a capacitor
context_page_description: Capacitors are manufactured in many forms, styles, lengths, girths, and from many materials. They all contain at least two electrical conductors separated by an insulating layer. Capacitors are widely used as parts of electrical circuits in many common electrical devices.
  Capacitors, together with resistors, and inductors, belong to the group of "passive components" used in electronic equipment. Although, in absolute figures, the most common capacitors are integrated capacitors, this article is concentrated on the various styles of capacitors as discrete components.
  Small capacitors are used in electronic devices to couple signals between stages of amplifiers, as components of electric filters and tuned circuits, or as parts of power supply systems to smooth rectified current. Larger capacitors are used for energy storage in such applications as strobe lights, as parts of some types of electric motors, or for power factor correction in AC power distribution systems. Standard capacitors have a fixed value of capacitance, but adjustable capacitors are frequently used in tuned circuits.
context_section_description: Discrete capacitors deviate from the ideal capacitor. An ideal capacitor only stores and releases electrical energy, with no dissipation. Capacitor components have losses and parasitic inductive parts. These imperfections in material and construction can have positive implications such as linear frequency and temperature behavior in class 1 ceramic capacitors. Conversely, negative implications include the non-linear, voltage-dependent capacitance in class 2 ceramic capacitors or the insufficient dielectric insulation of capacitors leading to leakage currents.
  All properties can be defined and specified by a series equivalent circuit composed out of an idealized capacitance and additional electrical components which model all losses and inductive parameters of a capacitor. In this series-equivalent circuit the electrical characteristics are defined by:
  C, the capacitance of the capacitor
  Rᵢₙₛᵤₗ, the insulation resistance of the dielectric, not to be confused with the insulation of the housing
  Rₗₑₐₖ, the resistance representing the leakage current of the capacitor
  RESR, the equivalent series resistance which summarizes all ohmic losses of the capacitor, usually abbreviated as "ESR"
  LESL, the equivalent series inductance which is the effective self-inductance of the capacitor, usually abbreviated as "ESL".
  Using a series equivalent circuit instead of a parallel equivalent circuit is specified by IEC/EN 60384-1.
caption: Series-equivalent circuit model of a capacitor
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