Transistor power amplifier

Posted: October 1st, 2022

Please help to answer this paper
JANUARY 2018 CONFIDENTIAL
INSTRUCTION: Answer ALL questions.
Please use the answer booklet provided
Question 1Trans
Figure 1 shows the BJT transistor power amplifier. Calculate:
The power dissipation (8 marks)
The efficiency (8 marks)
Figure 1
Describe the characteristic, advantages, disadvantages and applications of each of the classes (A, AB, B, and C) of power amplifiers (9 marks)
Question 2
(a) Given a voltage divider JFET amplifier that has VDD = 20 V, VP = -4 V, VGSQ = -0.5 V, R1 = 82 M, R2 = 11 M, RD = 2 k, RS = 610 , RL = 10 M and IDSS = 8 mA. Analyze the DC and AC performances of the given JFET amplifier. (25 marks)
 
Question 3
Construct the summing amplifier based on the Op-Amp circuit that consist of three input signals of V1, V2, and V3 and also one output Vout. (3 marks)
 
Prove the following equation for the summing amplifier: (8 marks)
 
Describe four different types of active filter and sketch their expected frequency responses
(8 marks)
Describe the construction, operation and characteristic of Shockley diode. (6 marks)
Question 4
For the given Figure 2
Determinegm0andgm(4 marks)
DetermineAvandAvsin the mid-frequency range(4 marks)
DeterminefHiandfHo(8 marks)
Determine the cut-off frequencies (2 marks)
Sketch the asymptotes of the Bode Plot defined by the cut-off frequencies of part (iv)
(3 marks)
Determine the high frequency response for the amplifier using the results of part (v) (4 marks)
Figure 2
END OF EXAMINATION PAPER
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