Analog Electronics - Study Mode

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[#36] Current stability of a CC amplifier can be increased by

(A) Reducing both emitter and base resistance

(B) Increasing both emitter and base resistance

(C) Reducing emitter resistance and increasing base resistance

(D) Increasing emitter resistance and decreasing base resistance

Correct Answer

(D) Increasing emitter resistance and decreasing base resistance

[#37] Three identical amplifiers with each one having a voltage gain of 50, input resistance of 1 kΩ and output resistance of 250 Ω, are cascaded. The open circuit voltage gain of the combined amplifier is

(A) 49 dB

(B) 51 dB

(C) 98 dB

(D) 102 dB

Correct Answer

(C) 98 dB

[#38] In a particular biasing circuit, the value of R E is about . . . . . . . .

(A) 10 kΩ

(B) 1 MΩ

(C) 100 kΩ

(D) 800 Ω

Correct Answer

(D) 800 Ω

[#39] In the circuit shown below, the switch was connected to position 1 at t < 0 and at t = 0, it is changed to position 2. Assume that the diode has zero voltage drop and a storage time t s . For 0 < t ≤ t s .V R s given by (all in Volts)

(A) V R = -5

(B) V R = +5

(C) 0 ≤ V R < 5

(D) -5 < V R < 0

Correct Answer

(A) V R = -5

[#40] A Darlington stage is shown in the figure is, if the trans-conductance Q 1 is g m1 and Q 2 is g m2 , then the overall trans-conductance gm is given by

(A) g m1

(B) 0.5 g m1

(C) g m2

(D) 0.5 g m2

Correct Answer

(C) g m2