Inductive and capacitive opposition that depends on frequency.
Inductive reactance X_L=ωL rises with frequency; capacitive X_C=1/(ωC) falls. Reactance does not dissipate power but stores and returns it. The circuit's net reactance sets the phase angle.
A 10 mH coil at 50 Hz has X_L≈3.14 Ω.
Reactance is the frequency-dependent part of impedance, so it explains why filters work and why inductive loads lower power factor.
Inductive and capacitive opposition that depends on frequency.
Reactance is the frequency-dependent part of impedance, so it explains why filters work and why inductive loads lower power factor.
Like resistance, it limits the ratio of voltage to current in the AC steady state, so it has the same unit.
An ideal reactance stores and returns energy each cycle and dissipates no average power, which is why reactive power is a separate quantity.
Typical applications include choosing a capacitor to cancel the inductive reactance of a motor, explaining why a choke blocks noise at high frequency and predicting the impedance of a coupling capacitor at audio frequency.
Study "Impedance" first (topic 40 of 106 in Electrical Engineering). It covers the groundwork this topic builds on.
X_L positive, X_C negative. At DC an inductor is short, capacitor open. Resonance when equal.
A 10 mH coil at 50 Hz has X_L≈3.14 Ω.
The next topic is "Power in AC circuits", which builds directly on this one.
It is classed as Intermediate in Electrical Engineering (topic 41 of 106). It is an intermediate topic. Work through the beginner topics in Electrical Engineering first.
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