FACULTY OF ENGINEERING-BIN-SUEF UNIVERSITY SHEET 1 Department: Electronics and Communications Engineering Lecturer: Associate Professor Fathy Mohamed Mustafa Course Title: Analog Electronic Circuits 1 Course Code: ECE-212 BJT 1- For the circuits in figure a, b, c, d, assumes that the transistors have very large β. Some measurements have been made on these circuits, with the results indicated in the figure. Find the values of the other labeled voltages and currents. 10 My best wishes Associate Professor Dr. Fathy M. Mustafa 10 2- Measurements on the circuits of figure a, b, c, produce labeled voltages as indicated. Find the value of β for each transistor. 3- For each of the circuits shown in figure a, b, c, d, find the emitter, base, and collector voltages and currents. Use β = 50, but assume independent of current level. 10 My best wishes Associate Professor Dr. Fathy M. Mustafa 10 4- For the circuit in Fig. P6.49 let VCC = 5 V, RC = 1 KΩ and RB= 20 KΩ. The BJT has β = 50. Find the value of VBB that result in the transistor operating (a) In the active mode with VC = 1 V; (b) At the edge of saturation; (c) Deep in saturation with βforced = 10. 10 My best wishes Associate Professor Dr. Fathy M. Mustafa 10 5- A single measurement indicates the emitter voltage of the transistor in the circuit of Fig. 1 to be 1.2 V. Under the assumption that = 0.7 V, what are VB, IB, IE, IC, VC, β, and α? (Note: Isn’t it surprising what a little measurement can lead to?). 6- For the transistor shown in Fig. 2, assume α = 1 and V = 0.5 V at the edge of conduction. What are the values of VE and VC for VB = 0 V? For what value of VB does the transistor cut off? Saturate? In each case, what values of V E and VC result? Figure 1 Figure 2 7- For the circuit shown in figure, find the labeled node voltages for β = 100. 10 My best wishes Associate Professor Dr. Fathy M. Mustafa 10 8- For the circuit shown in figure, draw a complete small-signal equivalent circuit for the BJT (use α = 0.99). Your circuit should show the values of all components, including the model parameters. What is the input resistance Rin? Calculate the overall voltage gain (Vo / VSig). 9- For the common-emitter amplifier shown in figure, let VCC = 15 V, R1 = 27 kΩ, R2 = 15 kΩ, RE = 2.4 kΩ, and RC = 3.9 kΩ. The transistor has β = 100. Calculate the dc bias current IC. If the amplifier operates between a source for which Rsig = 2 kΩ and a load of 2 kΩ, replace the transistor with its 10 My best wishes Associate Professor Dr. Fathy M. Mustafa 10 hybrid-π model, and find the values of Rin, and the overall voltage gain Vo / VSig. 10The amplifier of figure consists of two identical common-emitter amplifiers connected in cascade. Observe that the input resistance of the second stage, Rin2, constitutes the load resistance of the first stage. (a) For VCC = 9 V, R1 = 100 kΩ, R2 = 47 kΩ, RE = 3.9 kΩ, RC = 6.8 kΩ, and β = 100, determine the dc collector current and dc collector voltage of each transistor. (b) Draw the small-signal equivalent circuit of the entire amplifier and give the values of all its components. (c) Find Rin1 and Vb1 / VSig. for Rsig = 5 kΩ. (d) Find Rin2 and Vb2 / Vb1. 10 My best wishes Associate Professor Dr. Fathy M. Mustafa 10 11- For the emitter follower in figure, the signal source is directly coupled to the transistor base. If the dc component of Vsig is zero, find the dc emitter current. Assume β = 100. Neglecting ro, find Rin, the voltage gain Vo / Vsig, the current gain Io / Ii.and the output resistance Rout. 10 My best wishes Associate Professor Dr. Fathy M. Mustafa 10