Interview Questions.

Top 100+ Amplifier Interview Questions And Answers

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Top 100+ Amplifier Interview Questions And Answers

Question 1. Explain What Is An Operational Amplifier?

Answer :

An operational amplifier, abbreviated as op-amp, is largely a multi-degree, very excessive benefit, direct-coupled, terrible feedback amplifier that makes use of voltage shunt feedback to provide a stabilized voltage gain.

Question 2. State Assumptions Made For Analyzing Ideal Op-amp?

Answer :

Assumptions made for studying best op-amp are:

Infinite open-loop gain
Infinite enter impedance
Zero output impedance
Perfect balance
Infinite frequency bandwidth
Infinite slew charge
Infinite not unusual-mode rejection ratio
Nil waft of traits with temperature
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Question three. Explain What Are Differential Gain And Common-mode Gain Of A Differential Amplifier?

Answer :

When the difference of the 2 inputs implemented to the two terminals of a differential amplifier is amplified, the ensuing advantage is termed as differential advantage. But whilst the two input terminals are related to the equal enter supply then the advantage hooked up through the differential amplifier is known as the commonplace mode advantage.

Question four. Define Cmrr?

Answer :

CMRR is defined as the ratio of differential voltage gain to common-mode voltage advantage and it's far given as CMRR = Ad/Acm.

Question five. Explain Why Does An Op-amp Have High Cmrr?

Answer :

High CMRR ensures that the not unusual mode alerts consisting of noise are rejected efficiently and the output voltage is proportional best to the differential input voltage.

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Question 6. Explain Why Open-loop Op-amp Configurations Are Not Used In Linear Applications?

Answer :

When an op-amp is operated in the open-loop configuration, the output both is going to superb saturation or poor saturation stages or switches between nice and negative saturation tiers and for this reason clips the output above these stages. So open-loop op-amp configurations are not used in linear packages.

Question 7. List The Parameters That Should Be Considered For Ac And Dc Applications?

Answer :

The parameters to be taken into consideration for dc programs are:

Input offset voltage
Input offset modern
Input bias present day
Drift
The parameters to be taken into consideration for ac applications are:

Gain bandwidth product (GBW)
Rise time
Slew price
Full-strength response
AC noise
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Question 8. Define Offset Voltage As Applied To An Op-amp?

Answer :

Input offset voltage can be described as that voltage that is to be implemented among the enter terminals to stability the amplifier.

Question nine. Define Slew Rate?

Answer :

Slew rate of an op-amp is defined because the maximum rate of trade of output voltage consistent with unit time and is expresses in V/µs.

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Question 10. Explain What Is A Voltage Follower?

Answer :

Voltage follower is an electronic circuits wherein output voltage tracts the input voltage each in sign and significance.

Question 11. Explain What Are The Advantages Of Using A Voltage Follower Amplifier?

Answer :

Voltage follower has 3 particular characteristics viz. Extremely excessive input impedance, extraordinarily low output impedance and team spirit transmission advantage and is , therefore, a great circuit tool for use as a buffer amplifier.

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Question 12. In Explain What Way Is The Voltage Follower A Special Case Of The Non-inverting Amplifier?

Answer :

If feedback resistor is made 0 or R1 is made ∞(with the aid of keeping it open-circuited) in a noninverting amplifier circuit, voltage follower is obtained.

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Question thirteen. Explain What Is An Inverting Amplifier?

Answer :

In an inverting amplifier, the enter is attached to the minus or inverting terminal of op-amp.

Question 14. Explain What Are The Applications Of An Inverting Amplifier?

Answer :

Inverting amplifier is a totally versatile aspect and may be used for acting wide variety of mathematical stimulation together with analog inverter, paraphrase amplifier, phase shifter, adder, integrator, and differentiator.

Question 15. Explain What Is A Differential Amplifier?

Answer :

Differential amplifier is a mixture of inverting and noninverting amplifiers and amplifies the voltage distinction between enter strains neither of that's grounded.

Question 16. Give Examples Of Linear Circuits?

Answer :

Adder, subtractor, differentiator, integrator fall below the category of linear circuits.

Question 17. Explain What Is An Adder Or Summing Amplifier?

Answer :

Adder or summing amplifier is a circuit that gives an output voltage proportional to or equal to the algebraic sum of  or greater input voltages multiplied by using a steady benefit aspect.

Question 18. Explain What Is An Integrator?

Answer :

An integrator is a circuit that performs a mathematical operation called integration.

Electronic Circuits Interview Questions
Question 19. Explain What Are The Applications Of Integrator?

Answer :

Integrators are extensively used in ramp or sweep mills, filters, analog computer systems and so on.

Question 20. Op-amp Is Used Mostly As An Integrator Than A Differentiation. Explain Why?

Answer :

Op-amp is used broadly speaking as an integrator than a differentiator due to the fact in differentiator at high frequency, benefit is high and so excessive-frequency noise is likewise amplified which surely summary the differentiated sign.

Question 21. What Is Characteristic Of Ideal Op Amp?

Answer :

Characteristic of best OP AMP are

Infinite voltage benefit
Zero output impedance
Infinite enter impedance
Infinite slew charge
Characteristics now not drifting with temperature
Infinite bandwidth
Question 22. What Is Amplifier?

Answer :

Amplifier is a tool that makes sound louder and sign degree more.

Question 23. What Is The Formula For Non Inverting Amplifier?

Answer :

The components for non inverting amplifier is given as 1+Rf/R1.

Question 24. What Is Perfect Balance In Op Amp?

Answer :

Perfect stability is the characteristics of best OP AMP and if there is identical input implemented then we can get the output 0. In this circumstance it is referred to as perfect balance.

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Question 25. Which Opamp Don’t Have Feedback Loop?

Answer :

Comparator OP AMP (operational amplifier) don’t have feedback loop.

Question 26. Why Opamp Called Direct Coupled High Differential Circuit?

Answer :

OPAMP is known as direct coupled because the input of 1 OPAMP is inserted into the input of some other OPAMP. It is referred to as excessive advantage differential circuit because the distinction of the 2 enter is amplified.

Question 27. Why Opamp Called Operational Amplifier?

Answer :

OPAMP it's miles an immediate coupled excessive advantage differential enter amplifier. It is known as operational amplifier because it's far used for appearing distinctive features like differentiation, addition, integration, subtraction. It has infinite voltage advantage, countless slew fee, endless input impedance, zero output impedance, endless bandwidth.

Electronic Devices and Circuits Interview Questions
Question 28. What Is The Output Differentiation And Integrator?

Answer :

If we deliver the sinusoidal input in differentiator we are able to get the output of differentiator as a rectangular output. If we give the sinusoidal enter in integrator we are able to get the output of integrator as a ramp output.

Question 29. For The Cmrr To Be Infinite What Will Be The Condition?

Answer :

CMRR is described because the ratio of differential voltage gain (Ad) to common mode voltage advantage (Acm).

The formula for CMRR is given beneath:

CMRR = Ad/Acm

If Acm could be zero then only it will likely be countless.

Question 30. Explain What Is Meant By Small Signal Amplifier?

Answer :

When the enter signal is quite susceptible and produces much less small fluctuations in the output modern in evaluation to its quiescent value, the amplifier is referred to as the small sign or voltage amplifier.

Question 31. Explain What Is Meant By Phase Reversal?

Answer :

In a CE configuration, the output voltage will increase within the negative direction when the input signal voltage will increase within the wonderful route and vice-versa. This is called the phase reversal and and reasons a segment distinction of 180o among the enter signal and output voltage.

Question 32. Explain What Is An Ac Emitter Resistance?

Answer :

The dynamic resistance of the emitter-base junction diode is called the ac emitter resistance.

Question 33. Explain What Do You Mean By Operating Point?

Answer :

The zero sign values of IC and VCE are referred to as the operating factor. It is called working factor due to the fact the variations of IC and VCE take area about this point while sign is carried out. It is likewise known as the quiescent or Q-point.

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Question 34. Explain What Is Transistor Biasing?

Answer :

The proper waft of zero sign collector modern and the protection of proper collector emitter voltage during the passage of sign is known as the transistor biasing.

Question 35. Explain What Is Faithful Amplification?

Answer :

The procedure of elevating the energy of a vulnerable sign with none trade in its preferred shape is called faithful amplification.

Question 36. Explain What Is The Effect Of Removal Of Bypass Capacitor In A Ce Amplifier Circuit?

Answer :

Removal of skip capacitor in a CE amplifier circuit reasons excessive degeneration in the amplifier circuit and therefore reduction in voltage benefit.

Question 37. Explain Why Common-collector Circuit Is Known As An Emitter Follower?

Answer :

The CC circuit amplifier is called an emitter follower due to the fact in this circuit the output voltage on the emitter terminal follows the input sign applied to the bottom terminal.

Question 38. Explain What Are The Main Purposes For Which A Common-collector Amplifier May Be Used?

Answer :

For a commonplace collector amplifier, current benefit is as excessive as for CE amplifier, voltage gain is much less than unity, enter resistance is the highest and the output resistance is the bottom of all the 3 (CE, ,CC and CB) configurations. This circuit finds wide applications as a buffer amplifier among a excessive impedance source and a low load.




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