capacitive reactance

Capacitive reactance is an opposition to the change of voltage across an element.

Resonance occurs when the inductive and capacitive reactance's are equal.

If the tower is very short, it will have its capacitive reactance tuned out by this matching network.

Above this frequency, the inductor actually has capacitive reactance.

Since it is shorter than λ/4 the T antenna has a high capacitive reactance.

Then the inductive reactance is equal to the capacitive reactance.

Above the resonant frequency the capacitive reactance becomes the dominant part of the impedance.

These have a very low radiation resistance (and a high capacitive reactance) making them inefficient antennas.

An antenna shorter than a quarter wavelength presents capacitive reactance to the transmission line.

Capacitive reactance resists the change to voltage, causing the circuit current to lead voltage.

The additional opposition to current flow is called capacitive reactance and is due to the energy used when continuously reversing the electric field.

Very narrow bandwidth, requires loading coil to tune out the capacitive reactance and make it resonant.

Capacitive reactance is calculated from capacitance:

The ratio of peak voltage to peak current is due to capacitive reactance (denoted X).

The director element, on the other hand, being shorter than λ/2 has a capacitive reactance with the voltage phase lagging that of the current.

The helix adds inductance to cancel the capacitive reactance of the short radiator, making it resonant.

An antenna which is shorter than its resonant length is described as "electrically short", and exhibits capacitive reactance.

The suffix is to distinguish inductive reactance from capacitive reactance due to capacitance.

Capacitive reactance is inversely proportional to the rate of change of input voltage applied to the capacitor.

Capacitive reactance and inductive reactance contribute to the total reactance as follows.

In AC circuits, resistance forms part of the opposition to current flow in association with inductive and capacitive reactance.

Close to resonance the difference in reactance is quite small, and a small capacitive reactance is a big capacitor.

Enhanced performance stems from the capacitive reactance falling simultaneously with the inductive reactance increasing as the frequency increases.

To cancel the capacitive reactance, an inductance, called a loading coil, is inserted in between the feedline and the antenna terminal.

Capacitance (Capacitive reactance) :