ECEN 3250 f19_exam1s Boulder

1. [45 pts] In the circuit shown in Fig. 1, the Zener diode parameters are: Vz = Vzo = 4 V, r:= 0, IZmin = 0. When the diode is forward biased, the constant-voltage-drop (VD = 0.7 V) model applies. IR R 1 ΚΩ Iz Vcc + 5 V + VOUT TOUT Figure 1: a) For the following three values of louT, find the diode operating region: on (forwardbiased), off (reverse-biased), or breakdown, and solve the circuit to find Vour and IR: a.1 [10 pts] IoUT = 0 mA Breakdown Vout = Vz =4V TR= Fz = (Vce-Vout) /R = I mA i positive Iz is consestent with breakdown! a.2 [10 pts] loUT = 2 mA Reverse → Iz=0 IR= I at = 2nA Vout = Vec- IpR = 3 V Vout Vz → cousistent with reverse bias I a.3 [10 pts] IoUT = 6 mA Forward 7 Vout = Vp = -0,7 V Te= Vec-Voudt R = 5,7 wA Iz = TR- Iout = -0,3 wA Izo→ consistent with forward bias! 2 3 b) [15 pts] Sketch and label the DC transfer characteristic VOUT as a function of IOUT for 0 £ IOUT £ 10 mA in the diagram below.