TM 9-2547-3.Alternating Current - Continued(3)Inductive Reactance. The reactance of an inductor is calculated by the formula:_{XL }= 2 p fLWhere:_{XL}is the inductive reactance in ohms.fis the frequency in hertz.Lis the inductance in henries.pis the constant 3.14159.(4)Inductance. The total inductance for a circuit can be calculated using the formulas in figure 7-7.For inductors in series:^{L}T= L_{1} + L_{2} + L_{2}For more than two inductors in parallel:^{L}T=1L_{1} + L_{2} + L_{2}For two inductors in parallel^{L}T= L_{1} + L_{2}L_{1} + L_{2}Figure 7-7. Inductance Formulas(5)General Formula. As stated earlier the impedance of an AC circuit is the total opposition to the flow ofcurrent within the circuit. The general forms of the formulas for calculating impedance are given below:7-7