AC Components and Circuits Inductive Reactance
Section 22 Inductive Reactance I22 Inductive Reactance Definition Inductive Reactance Inductive reactance is the opposition to AC current caused by the alternating flux lines of an inductor.  Inductive reactance is similar to resistance in the sense that it opposes current flow. One of the major differences, however, is that the value of inductive reactance changes with the applied frequencyresistor values do not. Equation Inductive Reactance X_{L} = 2pfL Where  X_{L} = Inductive reactance in W
 f = Frequency in Hz
 L = Inductance in H
 These graphs show how inductive reactance responds to changes in frequency and the value of the inductor, itself. All other things being equal, the first diagram shows that X_{L} rises in proportion to the frequency. In fact, reactance is zero when 0 Hz (or DC power) is applied. The same is true when varying the value of inductance: the larger the value of the inductor, the greater amount of reactance to current.   More Examples Endless Examples & Exercises Given the value of an inductor and the frequency of the applied sinusoidal waveform, calculate the amount of inductive reactance.   Variations of the X_{L} Equation Solve for the value of the inductor: L =  X_{L}  2pf  This is a design situation where you need to select an inductor that will provide a known amount of reactance at a certain frequency. Solve for the frequency: f =  X_{L}  2pL  Example What value inductor is needed in a circuit that is to provide 1.2kW reactance at 240 kHz? 1. Select the appropriate equation: 2. Substitute the known values: L=  X_{L}  =  1.2x 10^{3}  2pf  6.28(240 x 10^{3})  3. Complete the math: L=  1.2x 10^{3}  = 0.000796  6.28(240 x 10^{3})  4. Present the solution: L=796mH
