Reactance

Related wiki pages: Capacitors, Inductors, Impedance

Reactance has some similarities with resistance, and can be though of in basic terms as reseistace to alternating currents. This includes currents at radio frequencies.

Capacitive Reactance
The impedance of a capacitor is given by the formula


 * $$Z = {1 \over j\omega C}$$

Where $$C$$ is the capacitance, $$\omega$$ is $$2 \pi f$$, and $$f$$ is the frequency. $$j$$ is "operator j" from phasor analysis.

In prasctical terms this leads to:

$$ X_c = \frac {1} {2\pi F C} $$ where


 * $$ X_c $$ is capacitive reactacnce
 * F is the frequency of operation in Hertz
 * C id the capacitance in Farads

Inductive Reactance
The impedance of an inductor is given by the formula


 * $$Z = j \omega L \,$$

where $$Z\,$$ is the impedance, $$\omega\,$$ is $$2 \pi f\,$$, and $$f\,$$ is the frequency. $$j\,$$ is "operator j" from phasor analysis.

In pracical terms this leads to:

$$ X_c = 2 \pi  F  L $$ where:
 * $$ X_c $$ is capacitive reactance
 * F is the frequency of operation in Hertz
 * L is the inductance in Henries

External links

Reactance calculator from Electronics 2000