Assume that the diode in the figure has on V_on = 0.7V, but is otherwise ideal. The magnitude of the current i₂ (in mA) is equal to __________.

The figure shows a half-wave rectifier with a 475 µF filter capacitor. The load draws a constant current I₀= 1 A from the rectifier. The figure also shows the input voltage V_i , the output voltage V_C and the peak-to-peak voltage ripple on V_C.The input voltage V_i is a triangle-wave with an amplitude of 10 V and a period of 1 ms.

The value of the ripple u (in volts) is ______________.

Resistor R₁ in the circuit below has been adjusted so that I₁ = 1 mA. The bipolar transistor Q1 and Q2 are perfectly matched and have very high current gain, so their base currents are negligible. The supply voltage V_cc is 6 V. The thermal voltage kT/q is 26 mV.

The value of R₂ (in $$\Omega $$ ) for which I₂ = 100 $$\mu {\rm A}$$ is ________.

Which one of the following statements is correct about an ac-coupled common- emitter amplifier operating in the mid-band region?

In the opamp circuit shown, the Zener diodes Z1 and Z2 clamp the output voltage V_o to +5 V or -5 V. The switch S is intially closed and is opened at time t = 0

The time t = t_{1 (in seconds) at which Vo changes state is _____.}

An opamp has a finite open loop voltage gain of 100. Its input offset voltage V_ios (= +5mV) is modeled as shown in the circuit below. The amplifier is ideal in all other respects. V_input is 25 mV.

The output voltage (in millivolts) is ________.

A speech signal is sampled at 8 kHz and encoded into PCM format using 8 bits/sample. The PCM data is transmitted through a baseband channel via 4-level PAM. The minimum bandwidth (in kHz) required for transmission is _________.

An information source generates a binary sequence $$\left\{ {{\alpha _n}} \right\}.{\alpha _n}$$ can take one of the two possible values −1 and +1 with equal probability and are statistically independent and identically distributed. This sequence is pre-coded to obtain another sequence $$\left\{ {{\beta _n}} \right\},$$ as $${\beta _n} = {\alpha _n} + k{\mkern 1mu} {\alpha _{n - 3}}$$ . The sequence $$\left\{ {{\beta _n}} \right\}$$ is used to modulate a pulse $$g(t)$$ to generate the baseband signal

$$x\left( t \right) = \sum\limits_{n = - \infty }^\infty {{\beta _n}g\left( {t - nT} \right),} $$ where $$g\left( t \right) = \left\{ {\matrix{ {1,} & {0 \le t \le T} \cr 0 & {otherwise} \cr } } \right.$$

If there is a null at $$f = {1 \over {3T}}$$ in the power spectral density of $$X(t)$$, then $$k$$ is _________.

Consider random process $$X(t) = 3V(t) - 8$$, where $$V$$ $$(t)$$ is a zero mean stationary random process with autocorrelation $${R_v}\left( \tau \right) = 4{e^{ - 5\left| \tau \right|}}$$. The power of $$X(t)$$ is _______.

An ideal band-pass channel 500Hz-2000 Hz is deployed for communication. A modem is designed to transmit bits at the rate of 4800 bits/s using 16-QAM. The roll-off factor of a pulse with a raised cosine spectrum that utilizes the entire frequency band is____________________

A discrete memoryless source has an alphabet $$({a_1},\,{a_2},\,{a_3},\,{a_4})\,$$ with corresponding probabilities$$\left( {{1 \over 2}\,\,,{1 \over 4},\,{1 \over 8},\,\,{1 \over 8}\,} \right)$$. The minimum required average codeword length in bits to represent this source for error-free reconstruction is__________________________

A binary communication system makes use of the symbols “zero” and “one”. There are channel errors. Consider the following events:
$${x_0}$$ : a " zero " is transmitted
$${x_1}$$ : a " one " is transmitted
$${y_0}$$ : a " zero " is received
$${y_1}$$ : a " one " is received

The following probabilities are given:
$$P({x_0}) = \,{3 \over 4},\,\left( {\,\left. {{y_0}} \right|{x_0}} \right) = \,{1 \over 2},\,\,and\,P\,\,\left( {\,\left. {{y_0}} \right|{x_1}} \right) = \,{1 \over 2}$$.
The information in bits that you obtain when you learn which symbol has been received (while you know that a " zero " has been transmitted) is _____________

The response of the system $$G\left(s\right)\;=\;\frac{s\;-\;2}{\left(s\;+\;1\right)\left(s\;+\;3\right)}$$ to the unit step input u(t) is y(t). The value of $$\frac{\mathrm{dy}}{\mathrm{dt}}\;\mathrm{at}\;\mathrm t\;=\;0^+\;\mathrm{is}$$ ___________.

In the feedback system shown below $$$G\left(S\right)\;=\frac1{(s^2\;+\;2s)}$$$ The step response of the closed-loop system should have minimum settling time and have no overshoot. The required value of gain k to achieve this is __________.

The number and direction of encirclements around the point −1 + j0 in the complex plane by the Nyquist plot of G(s) =$${{1 - s} \over {4 + 2s}}$$ is

In the feedback system shown below $${\rm{G(s) = }}{1 \over {\left( {s + 1} \right)\left( {s + 2} \right)\left( {s + 3} \right)}}$$ The positive value of 𝑘 for which the gain margin of the loop is exactly 0 dB and the phase margin of the loop is exactly zero degree is ____

The asymptotic Bode phase plot of $${\rm{G(s) = }}{k \over {\left( {s + 0.1} \right)\left( {s + 10} \right)\left( {s + {p_1}} \right)}},$$ with k and p_{1 both positive, is shown below. The value of p1 is ________}

Assume that all the digital gates in the circuit shown in the figure are ideal, the resistor 𝑅 = 10 𝑘Ω and the supply voltage is 5 𝑉. The D flip-flops D₁, D₂, D₃, D₄ and D₅ are initialized with logic values 0, 1, 0,1 and 0, respectively. The clock has a 30% duty cycle.

The average power dissipated (in mW) in resistor R is ______.

The state transition diagram for a finite state machine with states A, B and C, and binary inputs X, Y and Z, is shown in the figure.

Which one of the following statements is correct?

For the circuit shown in the figure, the delay of the bubbled NAND gate is 2ns and that of the counter is assumed to be zero

If the clock (Clk) frequency is 1 GHz, then the counter behaves as a

In an N bit flash ADC, the analog voltage is fed simultaneously to 2^N− 1 comparators. The output of the comparators is then encoded to a binary format using digital circuits. Assume that the analog voltage source V_in(whose output is being converted to digital format) has a source resistance of 75 Ω as shown in the circuit diagram below and the input capacitance of each comparator is 8 pF. The input must settle to an accuracy of 1/2 LSB even for a full scale input change for properconversion. Assume that the time taken by the thermometer to binary encoder is negligible. If the flash ADC has 8 bit resolution, which one of the following alternatives is closest to the maximum sampling rate?

A 4:1 multiplexer is to be used for generating the output carry of a full adder. A and B are the bits to be added while 𝐶in is the input carry and 𝐶out is the output carry. A and B are to be used as the select bits with A being the more significant select bit. Which one of the following statements correctly describes the choice of signals to be connected to the inputs $${I_0}$$, $${I_1}$$, $${I_2 }$$ and $${I_3}$$ so that the output is C$$_{out}$$?

Let the electric field vector of a plane electromagnetic wave propagating in a homogenous medium be expressed as $$E = \widehat x{E_x}\,{e^{ - j\left( {wt - \beta z} \right)}},$$ , where the propagation constant $$\beta $$ is a function of the angular frequency $$\omega $$. Assume that $$\beta \left( \omega \right)$$ and $${E_x}$$ are known and are real. From the information available, which one of the following CANNOT be determined?

A microwave circuit consisting of lossless transmission lines $$T_1$$ and $$T_2$$ is shown in the figure. The plot shows the magnitude of the input reflection coefficient $$\Gamma $$ as a function of frequency f. The phase velocity of the signal in the transmission lines is $$2\, \times \,{10^8}$$ m/s

A lossless microstrip transmission line consists of a trace of width w. It is drawn over a practically infinite ground plane and is separated by a dielectric slab of thickness 𝑡 and relative permittivity $${\varepsilon _r}\, > \,1$$. The inductance per unit length and the characteristic impedance of this line are L and $$Z_o$$ respectively. Which one of the following inequalities is always satisfied?

Consider the time-varying vector $$I = \,\hat x\,\,15\,\cos \,(\omega \,t) + \,\hat y\,5\,sin(\omega \,t)$$ in Cartesian coordinates, where $$\omega $$ > 0 is a constant. When the vector magnitude $$\left| I \right|$$ is at its minimum value, the angle $$\theta $$ that I makes with the x axis (in degree, such that $$0\, \le \,0 \le \,180$$) is _________________

Light from free space is incident at an angle $${\theta _1}$$ to the normal of the facet of a step-index large core optical fibre. The core and cladding refractive indices are $${n_1}\,\, = \,\,1.5$$ and $${n_2}\,\, = \,\,1.4$$ respectively.

The maximum value of $${\theta _1}$$ (in degrees) for which the incident light will be guided in the core of the fibre is ________ .

A uniform and constant magnetic field $$B=\widehat zB$$ exists in the $$\widehat z$$ direction in vacuum. A particle of mass m with a small charge q is introduced into this region with an initial velocity $$v=\widehat xv_x+\widehat zv_z$$. Given that B, m, q, v_x and v_z are all non-zero, which one of the following describes the eventual trajectory of the particle?

The parallel-plate capacitor shown in the figure has movable plates. The capacitor is charged so that the energy stored in it is E when the plate separation is d. The capacitor is then isolated electrically and the plates are moved such that the plate separation becomes 2d.

At this new plate separation, what is the energy stored in the capacitor, neglecting fringing effects?

Consider a region of silicon devoid of electrons and holes, with an ionized donor density of $${\mathrm N}_\mathrm d^+=10^{17}\;\mathrm{cm}^{-3}$$. The electric field at x = 0 is 0 V/cm and the electric field at x = L is 50 kV/cm in the positive x direction. Assume that the electric field is zero in the y and z directions at all points.

Given q = 1.6 × 10⁻¹⁹ coulomb, $$\varepsilon$$₀ = 8.85 × 10⁻¹⁴ F/cm, $$\varepsilon$$_r = 11.7 for silicon, the value of L in nm is ________.

The Ebers-Moll model of a BJT is valid

A long-channel NMOS transistor is biased in the linear region with V_DS = 50 mV and is used as a resistance. Which one of the following statements is NOT correct?

Transistor geometries in a CMOS inverter have been adjusted to meet the requirement for worst case charge and discharge times for driving a load capacitor C. This design is to be converted to that of a NOR circuit in the same technology, so that its worst case charge and discharge times while driving the same capacitor are similar. The channel lengths of all transistors are to be kept unchanged. Which one of the following statements is correct?

A voltage V_G is applied across a MOS capacitor with metal gate and p-type silicon substrate at T=300 K. The inversion carrier density (in number of carriers per unit area) for V_G = 0.8 V is $$2\,\, \times \,\,{10^{11}}\,\,\,\,\,\,c{m^{ - 2}}$$ . For $${V_G}\,\, = \,\,1.3\,\,V,$$ the inversion carrier density is $$4\,\,\, \times \,\,\,{10^{11}}\,\,\,\,c{m^{ - 2}}.$$ What is the value of the inversion carrier density for V_G = 1.8 V?

Consider a long-channel NMOS transistor with source and body connected together. Assume that the electron mobility is independent of V_GS and V_DS. Given,
g_m = 0.5$$\mu {\rm A}/V$$ for V_DS = 50 m V and V_GS = 2V,
g_d = $$8\mu {\rm A}/V$$ for V_GS = 2 V and V_DS = 0 V,
Where g_m =$${{\partial {{\rm I}_D}} \over {\partial {V_{GS}}}}\,\,and\,\,{g_d}\,\, = \,{{\partial {{\rm I}_D}} \over {\partial {V_{DS}}}}$$

The threshold voltage (in volts) of the transistor is

The value of $$x$$ for which the matrix $$A = \left[ {\matrix{ 3 & 2 & 4 \cr 9 & 7 & {13} \cr { - 6} & { - 4} & { - 9 + x} \cr } } \right]$$ has zero as an eigen value is __________.

The matrix $$A = \left[ {\matrix{ a & 0 & 3 & 7 \cr 2 & 5 & 1 & 3 \cr 0 & 0 & 2 & 4 \cr 0 & 0 & 0 & b \cr } } \right]$$ has det
$$(A)=100$$ and trace $$(A)=14.$$ The value of $$\left| {a - b} \right|$$ is ___________.

As $$x$$ varies from $$- 1$$ to $$3,$$ which of the following describes the behavior of the function $$f\left( x \right) = {x^3} - 3{x^2} + 1?$$

How many distinct values of $$x$$ satisfy the equation $$sin(x)=x/2,$$ where $$x$$ is in radians ?

Suppose $$C$$ is the closed curve defined as the circle $$\,\,{x^2} + {y^2} = 1\,\,$$ with $$C$$ oriented anti-clockwise. The value of $$\,\,\oint {\left( {x{y^2}dx + {x^2}ydx} \right)\,\,} $$ over the curve $$C$$ equals _______.

The ordinary differential equation $$\,\,{{dx} \over {dt}} = - 3x + 2,\,\,$$ with $$x(0)=1$$ is to be solved using the forward Euler method. The largest time step that can be used to solve the equation without making the numerical solution unstable is _________.

Consider the complex valued function $$f\left( z \right) = 2{z^3} + b{\left| z \right|^3}$$ where $$z$$ is a complex variable. The value of $$b$$ for which the function $$f(z)$$ is analytic is __________.

An 8 Kbyte ROM with an active low Chip Select input CS is to be used in an 8085 microprocessor based system. The ROM should occupy the address range 1000H to 2FFFH. Theaddress lines are designated as A15 to A0, where A15is the most significant address bit.Which one of the following logicexpressions will generate the correct $$\overline{CS}$$ signal for this ROM?

The figure shows an $$RLC$$ circuit with a sinusoidal current source.

At response, the ratio $$\left| {{{\rm I}_L}} \right|/\left| {{{\rm I}_R}} \right|$$, i.e., the ratio of the magnitudes of the inductor current phasor and the resistor current phasor, is _________.

The switch S in the circuit shown has been closed for a long time. It is opened at time t = 0 and remains open after that. Assume that the diode has zero reverse current and zero forward voltage drop. The steady state magnitude of the capacitor voltage V_C (in volts) is ____________.

In the circuit shown below, V_s is a constant voltage source and I_L is a constant current load

The value of I_L that maximizes the power absorbed by the constant current load is

The switch has been in position 1for a long time and abruptly changes to position 2 at t = 0. If time t is in seconds, the capacitor voltage V_C (in volts) for t>0 is given by

In the given circuit, each resistor has a value equal to 1 Ω.

What is the equivalent resistance across the terminals a and b?

The energy of the signal x(t) =$${{\sin (4\pi t)} \over {4\pi t}}$$ is ___________.

The Discrete Fourier Transform (DFT) of the 4-point sequence
$$x\left[ n \right]$$= {x[0], x[1], x[2], x[3]}
= {3, 2, 3, 4 } is
x[k] = {X[0], X[1], X[2], X[3]}
= {12, 2j, 0, -2j }
If $${X_1}$$ [k] is the DFT of the 12- point sequence$${X_1}$$[n] = {3, 0, 0, 2, 0, 0, 3, 0, 0, 4, 0, 0 },
The value of $$\left| {{{{X_1}[8]} \over {{X_1}[11]}}} \right|$$ is-----------------------.

A continuous-time filter with transfer function $$\,H(S) = {{2s + 6} \over {{s^2} + 6s + 8}}$$ is converted to a discrete time filter with transfer function $$G(Z) = {{2{z^2} - 0.5032\,z} \over {{z^2} - 0.5032z + k}}$$ so that the impulse response of the continuous-time filter, sampled at 2 Hz, is identical at the sampling instants to the impulse response of the discrete time filter, The value of k is _________________________.

Given (9 inches)^1/2 = (0.25 yards)^1/2, which one of the following statements is TRUE?

S, M, E and F are working in shifts in a team to finish a project. M works with twice the efficiency of others but for half as many days as E worked. S and M have 6 hour shifts in a day, whereas E and F have 12 hours shifts. What is the ratio of contribution of M to contribution of E in the project?