An alternative circuit for energizing an inductor and removing the stored energy without damaging a transistor is shown in Fig below. Here VCC 12 V, L 75 mH, and the zener breakdown voltage is VZ 20 V. The transistor switch opens and closes periodically with ton 20 ms and toff 50 ms. (a) Explain how the zener diode allows the switch to open. (b) Determine and sketch the inductor current iL(t) and the zener diode current iZ(t) for one switching period. (c) Sketch (p)(t) for the inductor and the zener diode. (d) Determine the average power absorbed by the inductor and by the zener diode.