Chapter 5, Problem 5.14TYU

For the circuit shown in Figure 5.44, assume circuit and transistor parameters of $R_B=240\text{Ω}$ , $V_{CC}=12\text{V}$ , $V_{BE}(on)=0.7\text{V}$ , $V_{CE}(sat)=0.1\text{V}$ , and $\beta =75$ . Assume that the load is a motor with an effective resistance of $R_C=5\text{Ω}$ .Calculate the currents and voltages in the circuit, and the power dissipated in the transistor for (a) ${\upsilon }_I=0$ and (b) ${\upsilon }_I=12\text{V}$ . (Ans. $i_B=i_C=0$ , ${\upsilon }_O=V_{CC}=12\text{V}$ ; (b) $i_B=47.1\text{mA}$ , $i_C=2.38\text{mA}$ , ${\upsilon }_O=0.1\text{V}$ , $P=0.27\text{1W}$ )