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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
Globally, the market for fixed capacitors was estimated at US$18 billion in 2008 for 1,400 billion (1.4 × 10 12) pieces. [75] This market is dominated by ceramic capacitors with estimate of approximately one trillion (1 × 10 12) items per year. [76] Detailed estimated figures in value for the main capacitor families are:
The ESR represents losses in the capacitor. In a low-loss capacitor the ESR is very small (the conduction is high leading to a low resistivity), and in a lossy capacitor the ESR can be large. Note that the ESR is not simply the resistance that would be measured across a capacitor by an ohmmeter. The ESR is a derived quantity representing the ...
The rated voltage U R is the maximum DC voltage or peak pulse voltage that may be applied continuously at any temperature within the rated temperature range T R (IEC/EN 60384-1). The voltage rating of electrolytic capacitors decreases with increasing temperature. For some applications it is important to use a higher temperature range.
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 ...
Class 1 ceramic capacitors are accurate, temperature-compensating capacitors. They offer the most stable voltage, temperature, and to some extent, frequency. They have the lowest losses and therefore are especially suited for resonant circuit applications where stability is essential or where a precisely defined temperature coefficient is ...
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.