Previous Year Questions
3 papers · 141 questions — organised by subject with solutions and explanations.
🎯 Practice smarter, not harder
Just sign in to unlock everything. Free for all students.
The diode in the circuit given below has = 0.7 V but is ideal otherwise. The current (in mA) in the resistor is _______.
In the circuit shown below, the Zener diode is ideal and the Zener voltage is 6 V. The output voltage (in volts) is_______.
In the circuit shown, assume that the opamp is ideal. The bridge output voltage (in mV) for = 0.05 is _______.
If the circuit shown has to function as a clamping circuit, then which one of the following conditions should be satisfied for the sinusoidal signal of period T ?
Assuming that the opamp in the circuit shown below is ideal, the output voltage (in volts) is________.
In the circuit shown, for switch SW in position A and for SW in position B. Assume that the opamp is ideal. The value of is ___________.
In the circuit shown in the figure, the BJT has a current gain ( ) of 50. For an emitter-base voltage = 600 mV, the emitter-collector voltage (in Volts) is _______.
In the bistable circuit shown, the ideal opamp has saturation levels of . The value of that gives a hysteresis width of 500 mV is ________.
In the circuit shown using an ideal opamp, the 3-dB cut-off frequency (in Hz) is _______.
In the circuit shown, = 80 mA and = 4 mA. Transistors are identical. Assume that the thermal voltage is 26 mV at . At , the value of the voltage (in mV) is_______.
For the circuit with ideal diodes shown in the figure, the shape of the output ( ) for the given sine wave input ( ) will be
In the ac equivalent circuit shown, the two BJTs are biased in active region and have identical parameters with . The open circuit small signal voltage gain is approximately _______.
In the circuit shown, assume that diodes are ideal. In the steady state condition, the average voltage (in Volts) across the 0.5 F capacitor is _____.
In the circuit shown, both the enhancement mode NMOS transistors have the following characteristic: . Assume that the channel length modulation parameter is zero and body is shorted to source. The min
In the circuit shown, assume that the diodes are ideal. The average value of voltage (in Volts), across terminals 'a' and 'b' is _________.
The circuit shown in the figure has an ideal opamp. The oscillation frequency and the condition to sustain the oscillations, respectively, are
For the voltage regulator circuit shown, the input voltage ( ) is % and the regulated output voltage ( ) is 10 V. Assume the opamp to be ideal. For a load drawing 200 mA, the maximum power dissipation
In the circuit shown, assume that the opamp is ideal. If the gain ( ) is -12, the value of R (in k ) is _____.
The input X to the Binary Symmetric Channel (BSC) shown in the figure is ' 1' with probability 0.8.The cross-over probability is 1/7. If the received bit Y = 0, the conditional probability that '1' wa
The transmitted signal in a GSM system is of 200 kHz bandwidth and 8 users share a common bandwidth using TDMA. If at a given time 12 users are talking in a cell, the total bandwidth of the signal rec
Consider a binary, digital communication system which uses pulses g(t) and -g(t) for transmitting bits over an AWGN channel. If the receiver uses a matched filter, which one of the following pulses wi
A source emits bit 0 with probability 1/3 and bit 1 with probability 2/3. The emitted bits are communicated to the receiver. The receiver decides for either 0 or 1 based on the received value R . It i
A random binary wave y(t) is given by where u(t) = u(t) - u(t -T), u(t) is the unit step function and is an independent random variable with uniform distribution in [0,T]. The sequence { } consists of
is an independent and identically distributed (i.i.d.) random process with equally likely to be +1 or -1. is another random process obtained as The autocorrelation function of , denoted by ,is
The variance of the random variable X with probability density function is_______.
A sinusoidal signal of 2 kHz frequency is applied to a delta modulator. The sampling rate and step-size of the delta modulator are 20,000 samples per second and 0.1 V, respectively. To prevent slope o
Consider the signal denotes the Hilbert transform of m(t) and the bandwidth of m(t) is very small compared to . The signal s(t) is a
A sinusoidal signal of amplitude A is quantized by a uniform quantizer. Assume that the signal utilizes all the representation levels of the quantizer. If the signal to quantization noise ratio is 31.
A message signal is used to modulate the phase of a carrier to get the modulated signal . The bandwidth of y(t).
The modulation scheme commonly used for transmission from GSM mobile terminals is
In the system shown in Figure (a), m(t) is a low-pass signal with bandwidth W Hz. The frequency response of the band-pass filter H(f) is shown in Figure (b). If it is desired that the output signal z(
A zero mean white Gaussian noise having power spectral density is passed through an LTI filter whose impulse response h(t) is shown in the figure. The variance of the filtered noise at t=4 is
The complex envelope of the bandpass signal , centered about Hz, is
The open-loop transfer function of a plant in a unity feedback configuration is given as . The value of the gain K(> 0) for which -1+ j2 lies on the root locus is_______.
The characteristic equation of an LTI system is given by The number of roots that lie strictly in the left half s-plane is _________.
The position control of a DC servo-motor is given in the figure. The values of the parameters are , , , and . The steady-state position response (in radians) due to unit impulse disturbance torque is_
A network is described by the state model as The transfer function is
The state variable representation of a system is given as The response y(t) is
A plant transfer function is given as . When the plant operates in a unity feedback configuration, the condition for the stability of the closed loop system is
For the signal flow graph shown in the figure, the value of is
The phase margin (in degrees) of the system is _______.
By performing cascading and/or summing/differencing operations using transfer function blocks , one CANNOT realize a transfer function of the form
The transfer function of a mass-spring-damper system is given by The frequency response data for the system are given in the following table. The unit step response of the system approaches a steady s
A lead compensator network includes a parallel combination of R and C in the feed-forward path. If the transfer function of the compensator is , the value of RC is ________.
Negative feedback in a closed-loop control system DOES NOT
The transfer function of a first-order controller is given as where K, a and b are positive real numbers. The condition for this controller to act as a phase lead compensator is
Consider the Bode plot shown in the figure. Assume that all the poles and zeros are real-valued. The value of (in Hz) is ___________.
A unity negative feedback system has the open-loop transfer function . The value of the gain K ( 0) at which the root locus crosses the imaginary axis is ________.
The output of a standard second-order system for a unit step input is given as . The transfer function of the system is
A unity negative feedback system has an open-loop transfer function . The gain for the system to have a damping ratio of 0.25 is ________.
The polar plot of the transfer function for will be in the
For the system shown in the figure, s = -2.75 lies on the root locus if K is _______.
The Boolean expression converted into the canonical product of sum (POS) form is
The figure shows a binary counter with synchronous clear input. With the decoding logic shown, the counter works as a
A function of Boolean variables X, Y and Z is expressed in terms of the min-terms as Which one of the product of sums given below is equal to the function F(X,Y,Z)?
Consider a four bit D to A converter. The analog value corresponding to digital signals of values 0000 and 0001 are 0 V and 0.0625 V respectively. The analog value (in Volts) corresponding to the digi
A mod-n counter using a synchronous binary up-counter with synchronous clear input is shown in the figure. The value of n is _______.
An SR latch is implemented using TTL gates as shown in the figure. The set and reset pulse inputs are provided using the push-button switches. It is observed that the circuit fails to work as desired.
The circuit shown consists of J-K flip-flops, each with an active low asynchronous reset ( input).The counter corresponding to this circuit is (
A 3-input majority gate is defined by the logic function M(a,b,c) = ab + bc + ca . Which one of the following gates is represented by the function ?
In the figure shown, the output Y is required to be .The gates G1 and G2 must be, respectively,
In the circuit shown, diodes are ideal, and the inputs are "0 V" for logic '0' and "10 V" for logic '1'. What logic gate does the circuit represent?
All the logic gates shown in the figure have a propagation delay of 20 ns. Let A = C = 0 and B = 1 until time t = 0. At t = 0, all the inputs flip (i.e., A = C = 1 and B = 0) and remain in that state.
A 1-to-8 demultiplexer with data input , address inputs (with as the LSB) and as the eight demultiplexed outputs, is to be designed using two 2-to-4 decoders (with enable E input and address inputs )
A three bit pseudo random number generator is shown. Initially the value of output is set to 111. The value of output Y after three clock cycles is
A universal logic gate can implement any Boolean function by connecting sufficient number of them appropriately. Three gates are shown. Which one of the following statements is TRUE?
In a source free region in vacuum, if the electrostatic potential , the value of constant c must be _______.
The longitudinal component of the magnetic field inside an air-filled rectangular waveguide made of a perfect electric conductor is given by the following expression The cross-sectional dimensions of
A vector field exists inside a cylindrical region enclosed by the surfaces = 1, z = 0 and z = 5. Let S be the surface bounding this cylindrical region. The surface integral of this field on is _______
The electric field of a plane wave propagating in a lossless non-magnetic medium is given by the following expression The type of the polarization is
The electric field intensity of a plane wave traveling in free space is given by the following expression In this field, consider a square area 10 cm x 10 cm on a plane x + y = 1. The total time-avera
Consider the 3 m long lossless air-filled transmission line shown in the figure. It has a characteristic impedance of 120 , is terminated by a short circuit, and is excited with a frequency of 37.5 MH
A coaxial cable is made of two brass conductors. The spacing between the conductors is filled with Teflon ( = 2.1, tan =0). Which one of the following circuits can represent the lumped element model o
The electric field of a uniform plane electromagnetic wave is The polarization of the wave is
Consider a uniform plane wave with amplitude of 10 V/m and 1.1 GHz frequency travelling in air, and incident normally on a dielectric medium with complex relative permittivity ( ) and permeability ( )
An air-filled rectangular waveguide of internal dimensions has a cutoff frequency of 6 GHz for the dominant mode. For the same waveguide, if the cutoff frequencyof the mode is 15 GHz, the cutoff frequ
A 200 m long transmission line having parameters shown in the figure is terminated into a load . The line is connected to a 400 V source having source resistance through a switch, which is closed at t
Consider a straight, infinitely long, current carrying conductor lying on the z-axis. Which one of the following plots (in linear scale) qualitatively represents the dependence of on r, where is the m
A coaxial capacitor of inner radius 1 mm and outer radius 5 mm has a capacitance per unit length of 172 pF/m. If the ratio of outer radius to inner radius is doubled, the capacitance per unit length (
The electric field component of a plane wave traveling in a lossless dielectric medium is given by . The wavelength (in m) for the wave is ___________.
A silicon sample is uniformly doped with donor type impurities with a concentration of . The electron and hole mobilities in the sample are 1200 and 400 /V-s respectively. Assume complete ionization o
In a MOS capacitor with an oxide layer thickness of 10 nm, the maximum depletion layer thickness is 100 nm. The permittivities of the semiconductor and the oxide layer are respectively.Assuming , the
For the NMOSFET in the circuit shown, the threshold voltage is , where > 0. The source voltage is varied from 0 to . Neglecting the channel length modulation, the drain current as a function of is rep
A region of negative differential resistance is observed in the current voltage characteristics of a silicon PN junction if
A dc voltage of 10 V is applied across an n-type silicon bar having a rectangular cross-section and a length of 1 cm as shown in figure. The donor doping concentration and the mobility of electrons ar
A piece of silicon is doped uniformly with phosphorous with a doping concentration of . The expected value of mobility versus doping concentration for silicon assuming full dopant ionization is shown
Which one of the following processes is preferred to form the gate dielectric ( ) of MOSFETs ?
The current in an enhancement mode NMOS transistor biased in saturation mode was measured to be 1 mA at a drain-source voltage of 5 V. When the drain-source voltage was increased to 6 V while keeping
If the base width in a bipolar junction transistor is doubled, which one of the following statements will be TRUE?
The built-in potential of an abrupt p-n junction is 0.75 V. If its junction capacitance at a reverse bias of 1.25 V is 5 pF, the value of (in pF) when = 7.25 V is ________.
An npn BJT having reverse saturation current A is biased in the forward active region with = 700 mV. The thermal voltage ( ) is 25 mV and the current gain ( ) may vary from 50 to 150 due to manufactur
The electric field profile in the depletion region of a p-n junction in equilibrium is shown in the figure. Which one of the following statements is NOT TRUE?
A MOSFET in saturation has a drain current of 1 mA for V. If the channel length modulation coefficient is 0.05 , the output resistance (in ) of the MOSFET is _________.
The energy band diagram and the electron density profile n(x) in a semiconductor are shown in the figures. Assume that , with = 0.1 V/cm and x expressed in cm. Given = 0.026V, . The electron current d
An n-type silicon sample is uniformly illuminated with light which generates electron-hole pairs per per second. The minority carrier lifetime in the sample is 1 . In the steady state, the hole concen
For a silicon diode with long P and N regions, the accepter and donor impurity concentrations are and , respectively. The lifetimes of electrons in P region and holes in N region are both 100 . The el
A 16 Kb (=16,384 bit) memory array is designed as a square with an aspect ratio of one (number of rows is equal to the number of columns). The minimum number of address lines needed for the row decode
In an 8085 microprocessor, the shift registers which store the result of an addition and the overflow bit are, respectively
Which one of the following 8085 microprocessor programs correctly calculates the product of two 8-bit numbers stored in registers B and C?
In an 8085 microprocessor, which one of the following instructions changes the content of the accumulator?
In the network shown in the figure, all resistors are identical with R = 300 . The resistance (in ) of the network is ______.
The 2-port admittance matrix of the circuit shown is given by
In the circuit shown, the average value of the voltage (in Volts) in steady state condition is________.
The damping ratio of a series RLC circuit can be expressed as
For the circuit shown in the figure, the Thevenin equivalent voltage (in Volts) across terminals a-b is ________.
In the circuit shown, at resonance, the amplitude of the sinusoidal voltage (in Volts) across the capacitor is ________.
In the circuit shown, the initial voltages across the capacitors and are 1V and 3V ,respectively. The switch is closed at time t = 0. The total energy dissipated (in Joules) in the resistor R until st
The voltage ( ) across the capacitor (in Volts) in the network shown is ______ .
The ABCD parameters of the following 2-port network are
In the circuit shown, the Norton equivalent resistance (in ) across terminals a-b is _______.
In the circuit shown, the voltage (in Volts) is _______.
In the circuit shown, the switch SW is thrown from position A to position B at time t = 0. The energy (in J) taken from the 3 V source to charge the 0.1 F capacitor from 0 V to 3 V is
At very high frequencies, the peak output voltage (in Volts) is ________.
In the circuit shown, switch SW is closed at t = 0. Assuming zero initial conditions, the value of (in Volts) at t = 1 sec is ________.
In the given circuit, the values of respectively are
In the circuit shown, the current I flowing through the 50 resistor will be zero if the value of capacitor C (in F) is ______.
In the given circuit, the maximum power (in Watts) that can be transferred to the load is_______.
An LC tank circuit consists of an ideal capacitor C connected in parallel with a coil of inductance L having an internal resistance R. The resonant frequency of the tank circuit is
For the discrete-time system shown in the figure, the poles of the system transfer function are located at
A realization of a stable discrete time system is shown in the figure. If the system is excited by a unit step sequence input x[n], the response y[n] is
The value is ______.
Consider the differential equation with initial condition x(0) =1. The response x(t) for t > 0 is
Suppose x[n] is an absolutely summable discrete-time signal. Its z-transform is a rational function with two poles and two zeroes. The poles are at . Which one of the following statements is TRUE for
Two causal discrete-time signals x[n]and y[n] are related as . If the z-transform of y[n] is , the value of x[2] is _______.
The signal is ideally sampled at a sampling frequency of 15 Hz. The sampled signal is passed through a filter with impulse response . The filter output is
The pole-zero diagram of a causal and stable discrete-time system is shown in the figure. The zero at the origin has multiplicity 4. The impulse response of the system is h[n]. If h[0] = 1, we canconc
Let be a periodic signal with period 16. Its DFS coefficients are defined by for all k . The value of the coefficient is _______.
Let with , where u(t) is unit step function. If the bilateral Laplace transform of x(t) is ; then the value of is _______.
The magnitude and phase of the complex Fourier series coefficients of a periodic signal x(t) are shown in the figure. Choose the correct statement from the four choices given. Notation: C is the set o
The impulse response of an LTI system can be obtained by
Consider two real sequences with time-origin marked by the bold value, Let be 4-point DFTs of , respectively. Another sequence is derived by taking 4-point inverse DFT of . The value of is ______.
Two sequences [a,b,c] and [A,B,C] are related as If another sequence [ p, q, r] is derived as, then the relationship between the sequences [ p, q, r] and [a, b, c] is
The result of the convolution is
Two sequences have the same energy. Suppose , where is a positive real number and u[n] is the unit step sequence. Assume Then the value of is _________.
Consider a continuous-time signal defined as where '*' denotes the convolution operation and t is in seconds. The Nyquist sampling rate (in samples/sec) for x(t) is _____.
Consider a four-point moving average filter defined by the equation , The condition on the filter coefficients that results in a null at zero frequency is
Consider the function where u(t) is the unit step function. The area under g(t) is _______.
Input x(t) and output y(t) of an LTI system are related by the differential equation . If the system is neither causal nor stable, the impulse response h(t) of the system is
The bilateral Laplace transform of a function is
Let the signal f(t) = 0 outside the interval where and are finite. Furthermore, . The region of convergence (RoC) of the signal's bilateral Laplace transform F(s) is
The waveform of a periodic signal x(t) is shown in the figure. A signal g(t) is defined by . The average power of g(t) is _______.