A real inductor can be modeled as an ideal inductor in series with an internal resistance as illustrated in the figure above.A time-varying current I is passed through a real inductor. At a time when I +4 A and dI/dt +14 A/s, the voltage drop across the inductor is observed to be Va - Vb +185 V. At another time when I +4 A and dI/dt -14 A/s, the observed voltage drop is V'a- V'b +43 V.
Ldi/dt +4i Vab, L(14) + R(4) 185 L(-14) + R(4) 43 System of linear eqns, add together; 8R 228, R 28.5 ohm
