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Capacitors and inductors as used in electric circuits are not ideal components with only capacitance or inductance.However, they can be treated, to a very good degree of approximation, as being ideal capacitors and inductors in series with a resistance; this resistance is defined as the equivalent series resistance (ESR) [1].
The loss tangent is defined by the angle between the capacitor's impedance vector and the negative reactive axis. If the capacitor is used in an AC circuit, the dissipation factor due to the non-ideal capacitor is expressed as the ratio of the resistive power loss in the ESR to the reactive power oscillating in the capacitor, or
Some types of capacitors, primarily tantalum and aluminum electrolytic capacitors, as well as some film capacitors have a specified rating value for maximum ripple current. Tantalum electrolytic capacitors with solid manganese dioxide electrolyte are limited by ripple current and generally have the highest ESR ratings in the capacitor family.
For electrolytic capacitors, ESR generally decreases with increasing frequency and temperature. [60] ESR influences the superimposed AC ripple after smoothing and may influence the circuit functionality. Within the capacitor, ESR accounts for internal heat generation if a ripple current flows across the capacitor. This internal heat reduces the ...
The temperature of the capacitor, which is established on the balance between heat produced and distributed, shall not exceed the capacitors maximum specified temperature. Hence, the ESR or dissipation factor is a mark for the maximum power (AC load, ripple current, pulse load, etc.) a capacitor is specified for. AC currents may be a:
Related to the capacitor ESR is accountable for internal heat generation if a #ripple current flows over the capacitor. This internal heat may influence the reliability of tantalum electrolytic capacitors. Generally, the ESR decreases with increasing frequency and temperature. [49]
The temperature of the capacitor, which is the net balance between heat produced and distributed, must not exceed the capacitor's maximum specified temperature. The ripple current for polymer e-caps is specified as a maximum effective (RMS) value at 100 kHz at upper rated temperature.
The heat flow can be modelled by analogy to an electrical circuit where heat flow is represented by current, temperatures are represented by voltages, heat sources are represented by constant current sources, absolute thermal resistances are represented by resistors and thermal capacitances by capacitors.