JNTU
JNTU B.Tech III INDUSTRIAL ELECTRONICS Previous Question Paper (February - 2023 - R16)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
PART - A
What is the need for DC amplifiers?
Answer
DC amplifiers are essential for amplifying signals that have very low frequency components or zero frequency (DC) levels, which AC-coupled amplifiers cannot process due to the blocking effect of coupling capacitors. They are necessary in applications such as instrumentation systems, medical equipment like ECG and EEG monitors, and control systems where the preservation of the signal's absolute magnitude and slow variations over time is critical for accurate measurement and signal processing.
Draw the circuit diagram of cascade amplifier.
Answer
A cascade amplifier is formed by connecting two or more amplifier stages in series, where the output of the first stage acts as the input to the subsequent stage. In a typical two-stage RC-coupled cascade amplifier, the collector of the first transistor is connected to the base of the second transistor through a coupling capacitor.
The circuit consists of biasing resistors (R1, R2), emitter resistors (RE) bypassed by capacitors (CE) for stability, and a coupling capacitor (Cc) that blocks DC while allowing AC signals to pass between stages. This configuration allows for higher overall voltage gain, which is the product of the individual gains of each stage.
What is over voltage protection?
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Compare fixed and variable IC voltage regulator.
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Give the applications of SCR.
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Discuss about thermal triggering and gate triggering.
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Why an isolation circuit is necessary for generating gate pulse?
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Classify choppers depending on the direction of current and voltage flows.
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Give the classification of timers and timer applications.
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Write down the principle of dielectric heating and induction heating.
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PART - B
Discuss the circuit diagram of cascode amplifier with and without biasing circuit.
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Explain three types of coupling methods used in multistage amplifiers.
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What is operational amplifier? Give the ideal and practical characteristics of op-amp.
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Derive the gain of an differential amplifier circuit.
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Discuss about series voltage regulator.
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Explain servo voltage stabilizer with neat circuit diagram.
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Define short circuit and thermal protection techniques. Discuss them.
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Explain variable IC voltage regulator.
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Discuss about the VI characteristics of SCR.
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Thyristors is a latching device, why?
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Explain the six distinct classes by which the SCR can be turned off.
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Describe thyristors general construction, operation with its V-I characteristics.
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What is DIAC? Discuss the triggering modes.
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Write down the principle and operation of step-up chopper.
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Explain the protection techniques in SCR.
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Discuss the following: i) Firing circuits ii) Converters.
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Explain briefly about different types of RC and digital timers.
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Discuss about voltage time base generator circuit.
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Derive the expression for the calculation of power which is converted into dielectric Heat.
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Discuss in detail about the ultrasonic generators and its Applications.
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