Chapter 2, Problem 2.10EP

Consider the circuit shown in Figure 2.39. The cut−in voltage of each diode is $V_{\gamma }=0.7\text{V}$ . (a) Let ${\upsilon }_I=5\text{V}$ . Assume both diodes are conducting. Is this a correct assumption? Why or why not? Determine $I_{R1},I_{D1},I_{D2}$ , and ${\upsilon }_O$ . (b) Repeat part (a) for ${\upsilon }_I=10\text{V}$ . (Ans. (a) $D_1$ is off, $I_{D1}=0$ , $I_{R1}=I_{D2}=0.754\text{mA}$ ${\upsilon }_O=3.72\text{V}$ ; (b) $I_{D1}=0.9\text{mA}$ , $I_{D2}=1.9\text{mA}$ , $I_{R1}=1.0\text{mA}$ , ${\upsilon }_O=8.3\text{V}$ )

Figure 2.39 Figure for Exercise Ex 2.10