If the antenna is shorter than a quarter wavelength, the feedpoint impedance will include capacitive reactance; this causes reflections on the feedline and a mismatch at the transmitter or receiver, even if the resistive component of the impedance is correct.
32.
The equivalent circuit of the antenna ( including loading coil ) is the series combination of the capacitive reactance of the antenna, the inductive reactance of the loading coil, and the radiation resistance and the other resistances of the antenna-ground circuit.
33.
The movable part ends with a flat foam element about the size of an daisy chain of two capacitors between contact pads and itself separated with thin soldermask, and thus " shorting " the contact pads with an easily detectable drop of capacitive reactance between them.
34.
For film capacitors, the dissipation factor tan " ? " will be specified in the relevant data sheets, instead of the ESR . The dissipation factor is determined by the tangent of the phase angle between the capacitive reactance " X"
35.
Antennas usually act as a capacitance, as antennas shorter than a quarter-wavelength have capacitive reactance . and relied instead on the capacitance inherent in the wire antenna ( in addition to significant parasitic capacitance in the coil ) to form the tuned circuit with the coil.
36.
In electric power systems, inductive reactance ( and capacitive reactance, however inductive reactance is more common ) can limit the power capacity of an AC transmission line, because power is not completely transferred when voltage and current are out-of-phase ( detailed above ).
37.
The voltage on a speaker wire depends on amplifier power; for a 100-watt-per-channel amplifier, the voltage will be about 30 volts RMS . At such voltage, a 1 percent loss will occur at 3, 000 ohms or less of capacitive reactance.
38.
However, human body capacitance is only about 100pF, which at 60Hz produces a capacitive reactance of about 25M?, which at 120V results in a current of about 5�A, which is about 200 times smaller than the talk ) 06 : 58, 25 April 2013 ( UTC)
39.
The total reactance at the angular frequency \ omega therefore is given by the geometric ( complex ) addition of a capacitive reactance ( Capacitance ) X _ C =-\ frac { 1 } { \ omega C } and an inductive reactance ( Inductance ) : X _ L = \ omega L _ { \ mathrm { ESL } }.
40.
The phase of the voltage across a purely reactive device ( a capacitor with an infinite resistance or an inductor with a resistance of zero ) " lags " the current by \ scriptstyle { \ pi / 2 } radians for a capacitive reactance and " leads " the current by \ scriptstyle { \ pi / 2 } radians for an inductive reactance.
