Chapter 8, Problem 8.43P

Consider the circuit in Figure 8.34. The supply voltages are $V^{+}=10\text{V}$ and $V^{-}=-10\text{V}$ , and the $R_3$ and $R_4$ resistor values are zero. The transistor parameters are: ${\beta }_1={\beta }_2=120$ , ${\beta }_3={\beta }_4=50$ , $I_{S1}=I_{S2}=2\times {10}^{-13}\text{A}$ , and $I_{S3}=I_{S4}=2\times {10}^{-12}\text{A}$ . (a) The range in output current is $-1\le i_o\le +\text{1A}$ . Determine the values of $R_1$ and $R_2$ such that the currents in ${\text{Q}}_1$ and ${\text{Q}}_2$ do not vary by more than 2:1. (b) Using the results of part (a), determine the quiescent collector currents in the four transistors for ${\upsilon }_I={\upsilon }_O=0$ . (c) Calculate the output resistance, excluding $R_L$ , for a quiescent output voltage of zero. Assume the source resistance of ${\upsilon }_I$ is zero.