Previous Year Questions
62 questions — organised by subject with solutions and explanations.
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For the circuit shown below, assume that the zener diode is ideal with a breakdown voltage of 6 volts. The waveform observed across R is
A regulated power supply, shown in figure below, has an unregulated input (UR) of 15 Volts and generates a regulated output . Use the component values shown in the figure. In the figure above, the gro
An n-channel depletion MOSFET has following two points on its curve: (i) =0 at =12 mA and (ii) =-6 Volts at =0 mA Which of the following Q point will given the highest trans conductance gain for small
For the circuit shown in the following figure, the capacitor C is initially uncharged. At t=0, the switch S is closed. The across the capacitor at t = 1 millisecond is In the figure shown above, the O
In the transistor amplifier circuit shown in the figure below, the transistor has the following parameters: , , , The capacitance can be assumed to be infinite. The small-signal gain of the amplifier
The input impedance ( ) and the output impedance ( ) of an ideal transconductance (voltage controlled current source) amplifier are
The minimum sampling frequency (in samples/sec) required to reconstruct the following signal from its samples without distortion. would be
The diagonal clipping in Amplitude Demodulation (using envelop detector) can be avoided it RC time-constant of the envelope detector satisfies the following condition, (here W is message bandwidth and
A message signal with bandwidth 10 kHz is Lower-Side Band SSB modulated with carrier frequency Hz. The resulting signal is then passed through a Narrow-Band Frequency Modulator with carrier frequency
Consider the following Amplitude Modulated (AM) signal, where : The AM signal gets added to a noise with Power Spectral Density given in the figure below. The ratio of average sideband power to mean n
The minimum step-size required for a Delta-Modulator operating at 32k samples/sec to track the signal (here u(t) is the unit-step function) x(t) = 125(u(t) - u(t - 1)) + (250-125t)(u(t - 1) - u(t - 2)
A zero-mean white Gaussian noise is passes through an ideal lowpass filter of bandwidth 10 kHz. The output is then uniformly sampled with sampling period = 0.03 msec. The samples so obtained would be
A source generates three symbols with probabilities 0.25, 0.25, 0.50 at a rate of 3000 symbols per second. Assuming independent generation of symbols, the most efficient source encoder would have aver
The following question refer to wide sense stationary stochastic processes It is desired to generate a stochastic process (as voltage process) with power spectral density S( ) = 16/(16 + ) by driving
A uniformly distributed random variable X with probability density function where u(.) is the unit step function is passed through a transformation given in the figure below. The probability density f
Let g(t)=p(t)*p(t) where * denotes convolution and p(t)=u(t)-u(t-1) with u(t) being the unit step function. An Amplitude Modulated signal is given as in the interval 0 t 1. One set of possible values
The following question refer to wide sense stationary stochastic processes The parameters of the system obtained in first order highpass R-c filter would be
In the following figure the minimum value of the constant "C", which is to be added to (t) such that (t) and (t) are different , is
The transfer function of a phase lead compensator is given by where The maximum phase shift provide by such a compensator is
The open-loop function of a unity-gain feedback control system is given by The gain margin of the system in dB is given by
Consider a unity-gain feedback control system whose open-loop transfer function is: With the value of "a" set for a phase - margin of , the value of unit-impulse response of the open-loop system at t=
In the system shown below, x(t) = (sint)u(t). In steady-state, the response y(t) will be
The Nyquist plot of for a closed loop control system, passes through (- 1, j0) point in the GH plane. The gain margin of the system in dB is equal to
The unit step response of a system starting from rest is given by The transfer function of the system is
A linear system is described by the following state equation The state transition matrix of the system is
The unit impulse response of a system is . For this system the steady-state value of the output for unit step input is equal to
The positive values of "K" and "a" so that the system shown in the figures below oscillates at a frequency of 2 rad/sec respectively are
Two D-flip-flops, as shown below, are to be connected as a synchronous counter that goes through the following sequence The inputs D0 and D1 respectively should be connected as,
For the circuit shown in figures below, two 4 - bit parallel - in serial - out shift registers loaded with the data shown are used to feed the data to a full adder. Initially, all the flip - flops are
The number of product terms in the minimized sum-of-product expression obtained through the following K - map is (where, "d" denotes don't care states)
The point P in the following figure is stuck at 1. The output f will be
A 4-bit D/A converter is connected to a free -running 3-bit UP counter, as shown in the following figure. Which of the following waveforms will be observed at ?
A new Binary Coded Pentary (BCP) number system is proposed in which every digit of a base-5 number is represented by its corresponding 3-bit binary code. For example, the base-5 number 24 will be repr
When a planes wave traveling in free-space is incident normally on a medium having , the fraction of power transmitted into the medium is given by
A medium of relative permittivity forms an interface with free-space. A point source of electromagnetic energy is located in the medium at a depth of 1 meter from the interface. Due to the total inter
A rectangular wave guide having mode as dominant mode is having a cut off frequency 18-GHz for the mode . The inner broad-wall dimension of the rectangular wave guide is
The electric field of an electromagnetic wave propagation in the positive direction is given by . The wave is
A medium is divide into regions I and II about x = 0 plane, as shown in the figure below. An electromagnetic wave with electric field is incident normally on the interface from region I . The electric
A 30-Volts battery with zero source resistance is connected to a coaxial line of characteristic impedance of 50 Ohms at t=0 second terminated in an unknown resistive load. The line length is that it t
In the circuit shown below, the switch was connected to position 1 at and at t = 0, it is changed to position 2. Assume that the diode has zero voltage drop and a storage time . For is given by (all i
Under low level injection assumption, the injected minority carrier current for an extrinsic semiconductor is essentially the
Find the correct match between Group 1 and Group 2
The values of voltage ( ) across a tunnel-diode corresponding to peak and valley currents are and respectively. The range of tunnel-diode voltage for which the slope of its characteristics is negative
The majority carriers in an n-type semiconductor have an average drift velocity v in a direction perpendicular to a uniform magnetic field B. The electric field E induced due to Hall effect acts in th
The phenomenon known as "Early Effect" in a bipolar transistor refers to a reduction of the effective base-width caused by
A heavily doped n-type semiconductor has the following data: Hole-electron ratio :0.4 Doping concentration : atoms/ Intrinsic concentration : atoms/ The ratio of conductance of the n-type semiconducto
The concentration of minority carriers in an extrinsic semiconductor under equilibrium is
Following is the segment of a 8085 assembly language program LXI SP, EFFF H CALL 3000 H : : : 3000 H : LXI H, 3CF4 PUSH PSW SPHL POP PSW RET On completion of RET execution, the contents of SP is
An I/O peripheral device shown in Fig. (b) below is to be interfaced to an 8085 microprocessor. To select the I/O device in the I/O address range D4H - D7H, its chip-select ( ) should be connected to
A 2 mH inductor with some initial current can be represented as shown below, where s is the Laplace Transform variable. The value of initial current is
A two-port network is represented by ABCD parameters given by If port-2 is terminated by , the input impedance seen at port-1 is given by
A negative resistance is connected to a passive network N having driving point impedance (s) as shown below. For (s) to be positive real,
In the figure shown below, assume that all the capacitors are initially uncharged. If Volts, is given by
The first and the last critical frequencies (singularities) of a driving point impedance function of a passive network having two kinds of elements, are a pole and a zero respectively. The above prope
In the two port network shown in the figure below, and respectively
A low-pass filter having a frequency response does not produce any phase distortions if
Consider the function f(t) having Laplace transform The final value of f(t) would be
A signal m(t) with bandwidth 500 Hz is first multiplied by a signal g(t) where The resulting signal is then passed through an ideal lowpass filter with bandwidth 1 kHz. The output of the lowpass filte
The Dirac delta function is defined as
If the region of convergence of is then the region of convergence of includes
Let x be Fourier Transform pair. The Fourier Transform of the signal x(5t - 3) in terms of X(j ) is given as
A system with input x[n] and output y[n] is given as y[n]= x[n] . The system is