Question

Homework 4 Due: June 26, 2019, at 5 pm. Note: Show all steps required to get to your answers and make sure to box them. Writing down answers to questions asked without any explanation(s) will not do it. Clarity should be a priority Moreover, the assigned textbook for this class is Sedra and Smith, Microelectronic Circuits, Seventh Edition, Oxford Univers ity Press. Make sure you have the proper book Reminder: In class, we have expressed the overall voltage gain of a (BJT or MOSFET) amplifier as A,(s) AM F(s) (s) where: AM is the mid-band voltage gain F1(s) w (in radians/seconds) being the low cutoff frequency, is the low frequency s+wL band factor WH (in radians/seconds) being the high cutoff frequency, is the high frequency = 1+- band factor Problem 1 Consider the CE amplifier shown on Figure P1.1. It contains a transistor Q1, whose characteristics are 27.010 pF, and C = 9.120 pF (pF stands for pico-farads, i.e., 10-12 F). B 150, C As you can see on Figure P1.2, simulation of the DC circuit in Multisim results in an operating point = 3.952 V, Iç = 6.050 mA). Qpoint(VCE 1. What type of transistor is Q1 on Figure P1.1 (or Figure P1.2)? 2. Consider mid-band frequency operation. Draw the overall small-signal equivalent circuit of the amplifier circuit operating at mid- band frequencies. Derive its mid-band frequency voltage gain A, а. Vout Ам b = 3. Consider low frequency operation. Draw the overall small-signal equivalent circuit of the amplifier circuit operating at low frequencies b. Using the Short Circuit Time Constant (SCTC) method, derive the low cutoff frequency fi=in Hz). Note that this involves finding the frequency poles (in Hz) f1, fi2,and fLg а 27T respectively caused by the coupling capacitors C1, C2, and C3 Consider high frequency operation 4. a. Draw the overall small-signal equivalent circuit of the amplifier circuit operating at high frequencies b. Using the Open Circuit Time Constant (OCTC) method, derive the high cutoff frequency H(in Hz). Note that this involves finding the frequency poles (in Hz) f, and fH2 2T - respectively caused by the device capacitors Cr and Cu Now, given your knowledge of AM, fi or wL, and fH or WH, Write out the overall expression of the voltage gain A, as a function of s = a + jw. 5. V1 6V R2206270 R4 10000 C2 2.2HF C1 Vout Q1 R1 2N2222A 5000 2.2uF R6 100000 C3 Vsig R3 6491 R5 47HF 327Q -6.0V V2 Figure P1.1 V1 6V R2 206270 R4 10000 : 6.05 mA PR1 (p-p): 0 A l(rms): 8.05 mA l(dc): 6.05 mA (freq): XMM1 Q1 2N2222A X Multimeter-XMM1 3.952 V R364910 :R5 dB A V 3270 Set... 6.0V V2 Figure P1.2

Answer 1

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