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EEE 3307 Homework Set 2 Problem 1. For all the transistors in the following, 75 β = . The results of some measurements are indicated on the following figures. Find the values of the other labeled currents, voltages, and/ or resistor values. Problem 2. For circuits shown in the following figures, the values of measured parameters are shown. Determine , β α and the other labeled currents and voltages. Sketch the DC load line and plot the Q-point.

Problem 3. Consider the circuit shown in the following figure. The measured value of the emitter voltage is 2V E V = . Determine , , , E C I I β α and EC V . Sketch the DC load line and plot the Q-point. Problem 4. For the circuit shown in the following figure, if 200 β = for each transistor, determine: 1 2 1 , , E E C I I V and 2 C V

Problem 7. The DC load line and Q-point of the circuit in Figure (a) are shown in Figure (b). For the transistor, β = 120. Find R E , R 1 , and R 2 such that the circuit is bias stable. Problem 8. For each transistor in the circuit in the following, β = 120. Determine the quiescent base, collector, and emitter currents in Q 1 and Q 2 . Also determine V CEQ1 and V CEQ2 .

Problem 9. The transistor parameters are β= 125 and V A =200V. A value of g m =200 mA/V is desired. Determine the collector current required, and then find r π and r 0 . Problem 10. The parameters of the transistor in the circuit in the following figure are β =150 and ∞ = A V . (a) Determine R 1 and R 2 to obtain a bias stable circuit with the Q-point in the center of the load line. (b) Determine the small signal voltage gain A v = v 0 / v s Problem 11. Consider the circuit shown in the following figure, where 4sin (mV) s v t ω = . Assume β =80. Determine 0 ( ) v t and 0 ( ) i t . What are the small signal voltage and current gains?

Problem 14. The transistor parameters for the circuit are β =180 and ∞ = A V , (1) Find I CQ and V CEQ (2) Plot the DC and AC load lines. (3) Calculate the small signal voltage gain. (4) Determine the input and output resistances R ib and R o. Problem 15. For the circuit in the figure, the transistor current gain is β = 80, R E = 0.5 kΩ, and R L =0.5 kΩ. Design the circuit to obtain a small- signal current gain of A i = i 0 / i s =8. Let V CC = 10 V, and the quiescent point Q is in the center of DC load line. (1) Find R 1, R 2 , and the output resistance R o. (2) What is the current gain if R L = 2 k Ω.

Problem 16. For the circuit shown in the following figure, the transistor parameters are β =100 and ∞ = A V . (1) Determine the DC voltages at the collector, base and emitter terminals (2) Find the input resistance R i (3) Determine the small signal voltage gain A v =v o / v s Problem 17. The parameters for each transistor in the circuit shown in the following figure are β =100 and ∞ = A V . Find: (1) the small signal parameters r π and r 0 for both transistors through DC analysis; (2) the small- signal voltage gain A v1 = v o1 / v s , assuming v o1 is connected to an open circuit, and determine the gain A v2 = v o / v o1 ; (3) the overall small signal voltage gain A v = v o / v s . Compare the overall gain with the product A v1 and A v2 , using the values calculated in part (2).