1
Design two stage cascaded amplifier to meet the following specifications:
Av ≥ 600, Ri ≥ 1MΩ, Sico ≤ 10, fL = 20Hz, Vo = 3V.
What would be the voltage gain for designing the circuit if both bypass capacitors are removed? To design, use suitable transistor from data sheet.
Av ≥ 600, Ri ≥ 1MΩ, Sico ≤ 10, fL = 20Hz, Vo = 3V.
What would be the voltage gain for designing the circuit if both bypass capacitors are removed? To design, use suitable transistor from data sheet.
20 M
2 (a)
Design a class B push-pull amplifier with appropriate biasing to minimize cross over distortion and using transformer coupling ratio for 8W of power. Use 12V DC supply. Assume RL = 5Ω. For designing circuit find efficiency at full load.
15 M
2 (b)
A BJJ has gm = 38m℧, rb'e = 5.9 kΩ, hie = 6kΩ, rbb' = 100Ω, Cb'c = 12 pF, cb'e = 63 pf and hfe = 224 and 1 KHz. Calculate α and β cut-off frequencies and fT.
5 M
3 (a)
Explain Millers theorem.
5 M
3 (b)
For a cascaded amplifier, show that the overall lower 3db freq FLT and higher 3dB frequency FH with n stages. Where
and
10 M
3 (c)
Determine the maximum safe power dissipation in a transistor if the rated power is 25W, maximum junction temperature Tjmax = 125?C. The transistor is mounted on a heat sink with ?cs = 1?C/W and ?sa = 5?C/W.
5 M
4 (a)
From the circuit determine value of resistors Re and R1, such that the operating point Icq = 10V and Vceq = 10V.
Given value of R2 = 10K, β =100 and VBE = 0.7V
Given value of R2 = 10K, β =100 and VBE = 0.7V
10 M
4 (b)
Draw the circuit of Darlington configuration and obtain expression for current gain and input resistance. Also explain the principle of Bootstrapping with the help of appropriate diagram.
10 M
5 (a)
From the given circuit, VBE = 0.6, βac = βdc = 100
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find (1)Q point (2)Ad (3)Ac (4)CMRR
find (1)Q point (2)Ad (3)Ac (4)CMRR
8 M
5 (b)
Derive the expression for Rif and R using equivalent circuit for -
(i) Voltage series negative feedback.
(ii) Current shunt negative feedback.
(i) Voltage series negative feedback.
(ii) Current shunt negative feedback.
12 M
6 (a)
Explain Barkhausen's criteria. Also derive the expression for frequency of oscillation of Wein Bridge Oscillator.
10 M
6 (b)(i)
Write short note on: Colpitt's Oscillator.
5 M
6 (b)(ii)
Write short note on: Clapp Oscillator.
5 M
7(a)
For the above circuit, compute voltage levels ad sketch the waveform of voltages at B1, C2 and B2, C2 for permanent state and quasi stable state.
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Use silicon transistors with rbb = 100Ω and hFE = 30
Use silicon transistors with rbb = 100Ω and hFE = 30
10 M
7(b)
Explain the various negative feedback topologies.
10 M
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