Operational Amplifier · Analog Electronics · GATE EE
Marks 1
1
The steady state output (Vout), of the circuit shown below, will
GATE EE 2022
2
Consider the circuit shown in the figure. In this circuit $$R = 1\,\,k\Omega ,$$ and $$C = 1\,\,\mu F.$$ The input voltage is sinusoidal with a frequency of $$50$$ $$Hz,$$ represented as a phasor with magnitude $${V_i}$$ and phase angle $$0$$ radian as shown in the figure. The output voltage is represented as a phasor with magnitude $${V_0}$$ and phase angle $$\delta $$ radian. What is the value of the output phase angle $$\delta $$ (in radian) relative to the phase angle of the input voltage?
GATE EE 2015 Set 1
3
Of the four characteristics given below, which are the major requirements for an instrumentation amplifier?
P. $$\,\,\,\,$$High common mode rejection ratio
Q. $$\,\,\,\,$$High input impedance
R. $$\,\,\,\,$$High linearity
S. $$\,\,\,\,$$High output impedance
P. $$\,\,\,\,$$High common mode rejection ratio
Q. $$\,\,\,\,$$High input impedance
R. $$\,\,\,\,$$High linearity
S. $$\,\,\,\,$$High output impedance
GATE EE 2015 Set 1
4
The filters $${F_1}$$ and $${F_2}$$ having characteristics as shown in figures $$(a)$$ and $$(b)$$ are connected as shown in Figure $$(c).$$
The cut-off frequencies of $$F1$$ and $$F2$$ are $${f_1}$$ and $${f_2}$$ respectively. If $${f_1}\, < \,{f_2},$$ the resultant circuit exhibits the characteristic of a
GATE EE 2015 Set 2
5
The operational amplifier shown in the figure is ideal. The input voltage (in Volt) is $${V_i} = 2\sin \left( {2\pi \times 2000t} \right).$$ The amplitude of the output voltage $${V_0}$$ (in Volt) is __________.
GATE EE 2015 Set 2
6
An operational-amplifier circuit is shown in the figure.
The output of the circuit for a given input $${V_i}$$ is
GATE EE 2014 Set 3
7
In the circuit shown below what is the output voltage $$\left( {{V_{out}}} \right)$$ in Volts If a silicon transfer $$Q$$ and an ideal op-amp are used?
GATE EE 2013
8
For the circuit shown below, the correct transfer characteristics is
GATE EE 2011
9
A low pass filter with a cut-off frequency of $$30Hz$$ is cascaded with a high pass filter with a cut off frequency of 20Hz. The resultant system of filters coil function as
GATE EE 2011
10
Given that the op-amp is ideal, the $$O/P$$ voltage $${V_0}$$ is
GATE EE 2010
11
The nature of feedback in the op-amp circuit shown is
GATE EE 2009
12
The circuit shown in figure is
GATE EE 2007
13
For given sinusoidal input voltage, the voltage waveform at point $$P$$ of the clamper circuit shown in figure will be
GATE EE 2006
14
For the circuit shown in figure with an ideal operational amplifier, the maximum phase shift of the output $${V_o}$$ with reference to the input $${V_{in}}$$ is
GATE EE 2003
15
The feedback factor for the circuit shown in fig. is
GATE EE 2000
16
The type of power amplifier which exhibits crossover distortion in its output is
GATE EE 2000
17
The circuit shown in figure uses an ideal op-amp working with $$+5V$$ and $$-5V$$ power supplies. The output voltage $${V_0}$$ is equal to
GATE EE 2000
18
A major advantage of active filters is that they can be realized without using
GATE EE 1997
19
The circuit shown in Figure, acts as a ... and for the given inputs, its output voltage is . . . . . $$V.$$
GATE EE 1997
20
A non inverting op - amp amplifier is shown in figure. The o/p voltage is
GATE EE 1996
21
Let the magnitude of the gain in the inverting op - amp amplifier circuit shown be $$x$$ with switch $${S_1}$$ open. When the switch $${S_1}$$ is closed, the magnitude of gain becomes.
GATE EE 1996
22
The common mode voltage of a unity gain (voltage follower) op-amp buffer in terms of its output voltage $${V_0}$$ is __________.
GATE EE 1995
23
Given figure, shows a non - inverting op - amp summer with $${V_1} = 2\,V$$ and $${V_2} = \, - 1V.$$ The output voltage $${V_0} = \_\_\_\_\_$$
GATE EE 1994
24
An ideal op-amp is used to make an inverting amplifier. The two input terminals of the op-amp are at the same potential because
GATE EE 1992
Marks 2
1
A difference amplifier is shown in the figure. Assume the op-amp to be ideal. The CMRR (in dB) of the difference amplifier is ________ (rounded off to 2 decimal places).
GATE EE 2024
2
Consider the OP AMP based circuit shown in the figure. Ignore the conduction drops of diodes $$D_1$$ and $$D_2$$. All the components are ideal and the breakdown voltage of the Zener is 5 V. Which of the following statements is true?
GATE EE 2023
3
The output impedance of a non-ideal operational amplifier is denoted by Zout. The variation in the magnitude of Zout with increasing frequency, f, in the circuit shown below, is best represented by
GATE EE 2022
4
The current gain (Iout/Iin) in the circuit with an ideal current amplifier given below is
GATE EE 2022
5
For the circuit shown below, assume that the $$OPAMP$$ is ideal.
Which one of the following is TRUE?
GATE EE 2017 Set 2
6
The approximate transfer characteristic for the circuit shown below with an ideal operational amplifier and diode will be
GATE EE 2017 Set 1
7
The op-amp shown in the figure has a finite gain $$A = 1000$$ and an infinite input resistance. A step voltage $${V_i} = 1\,\,mV$$ is applied at the input at time $$t = 0$$ as shown. Assuming that the operational amplifier is not saturated, the time constant (in millisecond) of the output voltage $${V_o}$$ is
GATE EE 2015 Set 1
8
The saturation voltage of the ideal op-amp shown below is $$ \pm 10\,V.$$ The output voltage $${V_O}$$ of the following circuit in the steady-state is
GATE EE 2015 Set 2
9
A hysteresis type $$TTL$$ inverter is used to realize an oscillator in the circuit shown in the figure.
If the lower and upper trigger level voltages are $$0.9$$ $$V$$ and $$1.7$$ $$V,$$ the period (in $$ms$$), for which output is LOW, is ____________.
GATE EE 2014 Set 3
10
The transfer characteristic of the Op-amp circuit shown in figure is
GATE EE 2014 Set 3
11
Given the Op-amps in the figure of ideal, the output voltage $${V_0}$$ is
GATE EE 2014 Set 1
12
In the figure shown, assume the op-amp to be ideal. Which of the alternatives gives the correct Bode plots for the transfer function $${{{V_O}\left( \omega \right)} \over {{V_i}\left( \omega \right)}}?$$
GATE EE 2014 Set 1
13
In the circuit shown below the op-amps are ideal. Then $${V_{out}}$$ in Volts is
GATE EE 2013
14
The following circuit has $$R = 10k\Omega ,\,C = 10\mu F.$$ The input voltage is a sinusoidal at $$50HZ$$ with an $$RMS$$ values of $$10V.$$ Under ideal conditions, the current $${{\rm I}_S}$$ from the source is
GATE EE 2009
15
An ideal op-amp circuit and its input waveform are shown in the figures. The $$o/p$$ wave form of this circuit will be
GATE EE 2009
16
A general filter circuit is shown in figure
The output of the filter in above is given to the circuit shown in figure The gain $${V_S}$$ frequency characteristic of the $$0/p$$ $$\left( {{V_0}} \right)$$ will be
GATE EE 2008
17
A waveform generator circuit using $$OPAMPs$$ is shown in the figure. It produces a triangular wave at point $$'P'$$ with a peak to peak voltage of $$5V$$ for $${v_1} = 0\,V.$$
If the voltage $${v_1}$$ is made $$+2.5$$ $$V,$$ the voltage waveform at $$'P'$$ will become.
GATE EE 2008
18
A general filter circuit is shown in figure
If $${R_1} = {R_2} = {R_A}$$ and $${R_3} = {R_4} = {R_B},$$ the circuit acts as a
GATE EE 2008
19
The block diagram of two types of half wave rectifiers are shown in figure. The transfer characteristics of the rectifiers are also shown within the block
It is desired to make full wave rectifier using two half wave rectifiers. The resultant circuit will be
GATE EE 2008
20
The input signal $${V_{in}}$$ shown in the figure is a $$1$$ $$kHz$$ square wave voltage that alternates between $$+7V$$ and $$-7V$$ with a $$50\% $$ duty cycle. Both transistors have the same current gain, which is large. The circuit delivers power to the load resistor $${R_L}.$$ What is the efficiency of this circuit for the given input? Choose the closest answer.
GATE EE 2007
21
The switch $$'S'$$ is the circuit of the figure is initially closed. It is opened at time $$t=0.$$ You may neglect the zener diode forward voltage drops. What is the behavior of $${V_{OUT}}$$ for $$t > 0$$
GATE EE 2007
22
A relaxation oscillator is made using op-amp as shown in figure. The supply Voltage of the op-amp are $$ \pm 12$$ the voltage waveform at point $$'p'$$ will be
GATE EE 2006
23
Consider the inverting amplifier, using an ideal operational amplifier shown in figure. The designer wishes to realize the input resistance seen by the small signal source to be as large as possible, while keeping the voltage gain between $$–10$$ and $$–25.$$ the upper limit on $${R_F}$$ is $$1\,M\Omega .$$ The value of $${R_1}$$ should be
GATE EE 2005
24
In the given figure, if the input is a sinusoidal signal, the output-will appear as shown
GATE EE 2005
25
In the active filter circuit shown in figure, if $$Q=1,$$ a pair of poles will be realized with $${\omega _0}$$ equal to
GATE EE 2004
26
The input resistance $${R_{IN}}\left( { = {V_x}/{I_x}} \right)$$ of the circuit in the figure is
GATE EE 2004
27
In the Schmitt trigger circuit shown in figure, if $${V_{CE}}\left( {sat} \right) = 0.1V,$$ the output logic low level $$\left( {{V_{OL}}} \right)$$ is
GATE EE 2004
28
Assuming the operational amplifier to be ideal, the gain $${V_{out}}/{V_{in}}$$ for the circuit shown in figure
GATE EE 2003
29
The output voltage$$\left( {{V_0}} \right)$$ of the Schmitt trigger shown in figure swings between $$+15V$$ and $$–15V.$$ Assume that the operational amplifier is ideal. The output will change from $$+15V$$ to $$–15V$$ when the instantaneous value of the input sine wave is
GATE EE 2002
30
An op-amp, having a slew rate of $$62.8$$ $$V/\mu \,$$sec, is connected in a voltage follower configuration. If the maximum amplitude of the input sinusoidal is $$10$$ Volts. Then the minimum frequency at which the slew rate limited distortion would set in at the output is
GATE EE 2001
31
For the oscillator circuit shown in figure, the expression for the time period of oscillations can be given by (where $$\tau = RC$$ )
GATE EE 2001
32
An active filter consisting of an op-amp, resistor $${R_1},\,\,{R_2},\,\,{R_3}$$ and two capacitors of value $$C$$ each, has a transfer function
$$T\left( s \right) = {{{{ - s} \over {\left( {{R_1}C} \right)}}} \over {{s^2} + {{2s} \over {\left( {{R_3}C} \right)}} + {1 \over {\left( {R{R_3}{C^2}} \right)}}}}$$
where, $$R = {R_1}||{R_2}$$
If $${R_1} = 2k\Omega ,{R_2} = 2/3\,k\Omega ,\,\,{R_3} = 200\,k\Omega $$ and $$C = 0.1\,\,\mu F,$$ determine the center frequency $${\omega _0},$$ gain $${A_0}$$ and the $$Q$$ of the filter.
$$T\left( s \right) = {{{{ - s} \over {\left( {{R_1}C} \right)}}} \over {{s^2} + {{2s} \over {\left( {{R_3}C} \right)}} + {1 \over {\left( {R{R_3}{C^2}} \right)}}}}$$
where, $$R = {R_1}||{R_2}$$
If $${R_1} = 2k\Omega ,{R_2} = 2/3\,k\Omega ,\,\,{R_3} = 200\,k\Omega $$ and $$C = 0.1\,\,\mu F,$$ determine the center frequency $${\omega _0},$$ gain $${A_0}$$ and the $$Q$$ of the filter.
GATE EE 2000
33
Match the following:
List - $${\rm I}$$ (Circuit)
List - $${\rm I}$$ (Circuit)
List - $${\rm II}$$ (Functions)
$$(P)$$$$\,\,\,\,\,$$ High-pass filter
$$(Q)$$$$\,\,\,\,\,$$ Amplifier
$$(R)$$$$\,\,\,\,\,$$ Comparator
$$(S)$$$$\,\,\,\,\,$$ Low-pass filter
GATE EE 1998
34
For the differential amplifier circuit shown in Figure, determine the differential gain, the common-mode gain and the common mode rejection ratio.
GATE EE 1997
35
In the following circuit the output $$'V'$$ follows an equation of the form
$${{{d^2}V} \over {d{t^2}}} + a.{{dV} \over {dt}} + bV = f\left( t \right).$$
Find $$a,b$$ and $$f(t)$$
$${{{d^2}V} \over {d{t^2}}} + a.{{dV} \over {dt}} + bV = f\left( t \right).$$
Find $$a,b$$ and $$f(t)$$
GATE EE 1992
36
The Circuit shown in figure is excited by the input wave form shown. Sketch the wave form of the output. Assume all the components are ideal
GATE EE 1992
37
With the ideal operational amplifiers, the circuit in figure simulates the equation
GATE EE 1991
Marks 5
1
For the op-amp circuit shown in figure. Determine the output voltage $${v_0}.$$ Assume that the op-amps are ideal
GATE EE 2001
2
A simple active filter is shown in figure. Assume ideal op-amp. Derive the transfer function $${v_0}/{v_i}$$ of the circuit, and state the type of the filter (i.e., high-pass, low-pass, band-pass, or band-reject). Determine the required values of $${R_1},{R_2}$$ and $$C$$ in order for the filter to have a $$3$$-$$dB$$ frequency of $$1$$ $$kHz,$$ a high frequency input resistance of $$100\,\,k\Omega $$ and a high frequency gain magnitude of $$10.$$
GATE EE 2001
3
The input voltage $${V_i}$$ in the circuit is a $$1$$ $$kHz$$ sine wave of $$1$$ $$V$$ amplitude. Assume ideal operational amplifiers with $$ \pm 15V\,\,DC$$ supply. Sketch on a single diagram the wave-forms of $${V_i},$$ $${V_1}$$ and $${V_0}$$ show, indicating the peak value of$${V_1}$$ and the average value $${V_0}$$.
GATE EE 1999
4
In the circuit of figure $${R_s} = 2\,k\Omega ,$$ $${R_L} = 5\,k\Omega $$ For the op-amp $$A = {10^5},$$
$${R_i} = 100\,k\Omega ,\,\,{R_0} = 50\,k\Omega .$$ For $${V_0} = 10V.$$
Calculate $${V_S}$$ and $${{{V_0}} \over {{V_S}}}$$ and estimate the input resistance of the circuit,
$${R_i} = 100\,k\Omega ,\,\,{R_0} = 50\,k\Omega .$$ For $${V_0} = 10V.$$
Calculate $${V_S}$$ and $${{{V_0}} \over {{V_S}}}$$ and estimate the input resistance of the circuit,
GATE EE 1998
5
Figure below shows an op-amp amplifier. Find the output voltage in steady state condition where $$(i)$$ switch is open $$(ii)$$ $$S$$ is closed
GATE EE 1994
6
$$(a)$$ For the circuit shown in figure
$$(i)$$ Calculate the transfer function $${{{V_0}} \over {{V_i}}}$$
$$(ii)$$ plot the amplitude and phase response as a function for $$R = {R_1}$$
GATE EE 1992
7
In the figure shown, assume that the zener diode and operational amplifier to be ideal.
$$(a)$$ Draw the equivalent circuit and evaluate the gain $$\left( {{V_0}\,\,vs\,\,{V_i}} \right)$$ of the circuit for
$$(i)$$ $${V_i} \le 0$$ $$\,\,\,\,\,\left( {ii} \right)\,\,\,0 < {V_i} < 5V\,\,\,\,\,\,$$ $$\,\,\,\,\,\left( {iii} \right)\,\,\,{V_i} > 5V\,\,\,\,\,\,$$
$$(b)$$ Sketch the gain $$\left( {{V_0}\,\,\,{V_s}\,\,\,{V_i}} \right)$$ characteristics of the above circuit and label the salient features.
GATE EE 1991