Electronics-Amplifiers and Oscillators [IAS (Admin.) Mains Physics]: Questions 1 - 6 of 14

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Question 1

Appeared in Year: 2003

Describe in Detail Subjective▾

In the following circuit, show that the stability factor S is given by

Where

Figure Shows the Circuit

(20 Marks)

Edit

Explanation

It is desirable and necessary to keep constant in the face of variations of (sometimes represents as ) . The extent to which a biasing circuit is successful in achieving this goal is measured by stability factor S. It is defined as the rate of change of coll…

… (547 more equations, 22 figures) …

Question 2

Appeared in Year: 2010

Describe in Detail Subjective▾

Draw a two stage RC coupled transistor amplifier. Plot the frequency response and indicate the lower and upper cut off frequencies and the bandwidth.

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Explanation

  • Fig (1) shows how to couple two stages of amplifiers using resistance – capacitance (RC) coupling scheme. In this scheme, the signal developed across the collector resister of the first stage Is coupled to the base of thee second stage through the capacitor . The coupling capacitor block…

… (277 more equations, 11 figures) …

Question 3

Appeared in Year: 2011

Describe in Detail Subjective▾

Draw the common – base amplifier circuit, using an transistor and briefly discuss its working. (Marks 15)

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Explanation

In common base configuration, input is connected between emitter and base and output is taken across collector and base. This base is common between input and output circuits.

The common – base amplifier provides high voltage gain with a maximum current of . …

… (436 more equations, 46 figures) …

Question 4

Appeared in Year: 2003

Describe in Detail Subjective▾

Explain the principle of feedback in an amplifier. What are the advantages of negative feedback? (Marks: 8)

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Explanation

Feedback is the process of taking a part of output signal and feeding it back to the input circuit. Fig (1) shows a block diagram of a basic simplifier. Here, is the input signal and the output. If A is the voltage gain of the simplifier, the output is related to the input

… (177 more words, 6 figures) …

Question 5

Appeared in Year: 2020

Describe in Detail Subjective▾

An amplifier has bandwidth of 500 kHz and voltage gain of 100. What should be the amount of negative feedback if the amplifier bandwidth is extended to 5 MHz? What will be the new gain after negative feedback is introduced?

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Explanation

Effect on cut-off frequencies:

Negative feedback decreases lower cut-off frequency and increases higher cut-off frequency.

… (108 more equations) …

Question 6

Appeared in Year: 2020

Describe in Detail Subjective▾

A filter capacitor C is used to smooth out the pulses from the full-wave rectifier as shown in the figure below:

Find the Value of C so that the steady current supply to load can be maintained.

The Value of C So That the Steady Current Supply
Edit

Explanation

For rectifier we can write:

Since, the output is a rectified wave, we have:

The Output is a Rectified Wave

… (54 more equations, 9 figures) …