Equivalent series inductance
Encyclopedia
Equivalent series inductance (ESL) is an effective inductance
Inductance
In electromagnetism and electronics, inductance is the ability of an inductor to store energy in a magnetic field. Inductors generate an opposing voltage proportional to the rate of change in current in a circuit...

 that is used to describe the inductive part of the impedance
Electrical impedance
Electrical impedance, or simply impedance, is the measure of the opposition that an electrical circuit presents to the passage of a current when a voltage is applied. In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current circuit...

 of certain electrical components.

Overview

The theoretical treatment of devices such as capacitor
Capacitor
A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...

s and resistor
Resistor
A linear resistor is a linear, passive two-terminal electrical component that implements electrical resistance as a circuit element.The current through a resistor is in direct proportion to the voltage across the resistor's terminals. Thus, the ratio of the voltage applied across a resistor's...

s tends to assume they are ideal or "perfect" devices, contributing only capacitance or resistance to the circuit. However, all physical devices are connected to a circuit through conductive leads and paths, which contain inherent, usually unwanted, inductance. This means that physical components contain some inductance in addition to their other properties.

An easy way to deal with these inherent inductances in circuit analysis is by using a lumped element model
Lumped element model
The lumped element model simplifies the description of the behaviour of spatially distributed physical systems into a topology consisting of discrete entities that approximate the behaviour of the distributed system under certain assumptions...

 to express each physical component as a combination of an ideal component and a small inductor
Inductor
An inductor is a passive two-terminal electrical component used to store energy in a magnetic field. An inductor's ability to store magnetic energy is measured by its inductance, in units of henries...

 in series, the inductor having a value equal to the inductance present in the non-ideal, physical device.

Effects of ESL

Ideally, the impedance
Electrical impedance
Electrical impedance, or simply impedance, is the measure of the opposition that an electrical circuit presents to the passage of a current when a voltage is applied. In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current circuit...

 of a capacitor
Capacitor
A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...

 falls with increasing frequency at 10 dB/decade. However, due partly to the inductive properties of the connections, and partly to non-ideal characteristics of the capacitor material, real capacitors also have inductive properties whose impedance rises with frequency at 10 dB/decade. At the resonance frequency the sum of both is minimal, above it the parasitic series inductance of the capacitor dominates.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK