Dielectric absorption

Dielectric absorption is the name given to the effect by which a capacitor, that has been charged for a long time, discharges only incompletely when briefly discharged.wikipedia
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Capacitor

capacitorscapacitivecondenser
Dielectric absorption is the name given to the effect by which a capacitor, that has been charged for a long time, discharges only incompletely when briefly discharged.
Capacitors made with any type of dielectric material show some level of "dielectric absorption" or "soakage".

Dielectric

dielectricsdielectric relaxationpolarization
Although an ideal capacitor would remain at zero volts after being discharged, real capacitors will develop a small voltage from time-delayed dipole discharging, a phenomenon that is also called dielectric relaxation, "soakage", or "battery action". For some dielectrics, such as many polymer films, the resulting voltage may be less than 1–2% of the original voltage, but it can be as much as 15% for electrolytic capacitors. Charging a capacitor (due to a voltage between the capacitor plates) causes an electric field to be applied to the dielectric between the electrodes. This change in the molecular dipoles is called oriented polarization and also causes heat to be generated, resulting in dielectric losses (see dissipation factor).

Relaxation (physics)

relaxation timerelaxationrelax
When the capacitor is discharging, the strength of the electric field is decreasing and the common orientation of the molecular dipoles is returning to an undirected state in a process of relaxation.
Very long relaxation times are responsible for dielectric absorption.

Bleeder resistor

In order to prevent shocks, most very large capacitors are shipped with shorting wires that need to be removed before they are used and/or permanently connected bleeder resistors.
This is due to a property called dielectric absorption, in which energy stored in the dielectric during use is released gradually over time.

Film capacitor

filmfilm capacitorsPlastic film capacitors
In addition, PP film capacitors have the lowest dielectric absorption, which makes them suitable for applications such as VCO timing capacitors, sample-and-hold applications, and audio circuits.

Dielectric spectroscopy

Electrochemical impedance spectroscopyImpedance spectroscopyAC impedance spectroscopy

Volt

VkVvolts
Although an ideal capacitor would remain at zero volts after being discharged, real capacitors will develop a small voltage from time-delayed dipole discharging, a phenomenon that is also called dielectric relaxation, "soakage", or "battery action".

Polymer

polymershomopolymerpolymeric
For some dielectrics, such as many polymer films, the resulting voltage may be less than 1–2% of the original voltage, but it can be as much as 15% for electrolytic capacitors.

Electrolytic capacitor

electrolytic capacitorselectrolyticAluminum capacitors
For some dielectrics, such as many polymer films, the resulting voltage may be less than 1–2% of the original voltage, but it can be as much as 15% for electrolytic capacitors.

High-voltage cable

cablehigh voltage cableCable accessories
When disconnected at one or both ends, DC high-voltage cables can also "recharge themselves" to dangerous voltages.

Electric field

electricelectrostatic fieldelectrical field
Charging a capacitor (due to a voltage between the capacitor plates) causes an electric field to be applied to the dielectric between the electrodes.

Torque

moment armmomentlever arm
This field exerts a torque on the molecular dipoles, causing the directions of the dipole moments to align with the field direction.

Dipole

dipole momentdipolarmolecular dipole moment
This field exerts a torque on the molecular dipoles, causing the directions of the dipole moments to align with the field direction.

Dielectric loss

loss tangentdielectric lossesloss
This change in the molecular dipoles is called oriented polarization and also causes heat to be generated, resulting in dielectric losses (see dissipation factor).

Dissipation factor

dissipationinsulation lossesloss tangent
This change in the molecular dipoles is called oriented polarization and also causes heat to be generated, resulting in dielectric losses (see dissipation factor).

Time constant

time-constantThermal time constant63%
The orientation of the dipoles does not follow the electric field synchronously, but is delayed by a time constant that depends on the material.

Hysteresis

hysteretichysteresis loophysteresis loss
This delay corresponds to a hysteresis response of the polarization to the external field.

Remanence

remanentremanent magnetizationremanent magnetism
This is like an electrical version of magnetic remanence.

Exponential decay

mean lifetimedecay constantexponentially
The oriented dipoles will be discharged spontaneously over time and the voltage at the electrodes of the capacitor will decay exponentially.

Tantalum capacitor

tantalum electrolytic capacitorsTantalum electrolytic capacitortantalum

Sample and hold

sample-and-holdS/Hsample-and-hold amplifiers
For sensitive analog circuits such as sample and hold circuits, integrators, charge amplifiers or high-quality audio circuits, Class-1 ceramic or polypropylene capacitors instead of Class-2 ceramic capacitors, polyester film capacitors or electrolytic capacitors are used.

Operational amplifier applications

inverting amplifierintegratorintegrators
For sensitive analog circuits such as sample and hold circuits, integrators, charge amplifiers or high-quality audio circuits, Class-1 ceramic or polypropylene capacitors instead of Class-2 ceramic capacitors, polyester film capacitors or electrolytic capacitors are used.

Charge amplifier

charge-sensitive preamplifier
For sensitive analog circuits such as sample and hold circuits, integrators, charge amplifiers or high-quality audio circuits, Class-1 ceramic or polypropylene capacitors instead of Class-2 ceramic capacitors, polyester film capacitors or electrolytic capacitors are used.