Analog Electronics - Study Mode

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[#271] The value of h FE (the hybrid parameters) of a Common-Emitter (CE) connection of a Bipolar Junction Transistor (BJT) is given as 250. What is the value of α dc (ratio of collector current to emitter current), for this BJT?

(A) 0.436

(B) 0.656

(C) 0.874

(D) 0.996

Correct Answer

(D) 0.996

[#272] Consider the following statements regarding an op-amp: 1. All types of negative feedback reduce nonlinear distortion. 2. All types of negative feedback reduce the output offset voltage. 3. Non-inverting (current and voltage) feedback increases the input impedance. 4. Inverting (current and voltage) feedback decreases input impedance. Which of the above statements is/are correct?

(A) 1 only

(B) 2 and 3 only

(C) 2 and 4 only

(D) 1, 2, 3 and 4

Correct Answer

(D) 1, 2, 3 and 4

[#273] For the operational amplifier circuit shown, the output saturation voltages are ±15 V. The upper and lower threshold voltages for the circuit are, respectively,

(A) +5 V and -5 V

(B) +7 V and -3 V

(C) +3 V and -7 V

(D) +3 V and -3 V

Correct Answer

(B) +7 V and -3 V

[#274] In the given block diagram, which is the sampling element?

(A) Voltage divider using R 1 and R 2

(B) Transistor Q 2

(C) Op-amp

(D) R 3 and Zener diode

Correct Answer

(A) Voltage divider using R 1 and R 2

[#275] Bootstrap voltage sweep generator uses

(A) negative feedback

(B) positive feedback

(C) both negative and positive feedbacks simultaneously

(D) no feedback

Correct Answer

(B) positive feedback