The sinusoidal ac source in the figure has an rms value of $${{20} \over {\sqrt 2 }}\,V.$$ Considering all possible values of $${R_L},\,\,$$ the minimum value of $${R_s}$$ in $$\Omega $$ to avoid burnout of the Zener diode is ______.

Assuming the diodes to be ideal in the figure, for the output to be clipped, the input voltage $${V_i}$$ must be outside the range

The transistor in the given circuit should always be in active region. Take $${V_{CE\left( {sat} \right)}} = 0.2\,\,V,\,\,\,{V_{BE}} = 0.7\,\,V.\,\,\,$$ The maximum value of $${R_C}$$ in $$\Omega $$ which can be used, is __________.

An oscillator circuit using ideal op-amp and diodes is shown in the figure.

The duration for $$+ve$$ part of the cycle $$\Delta {t_1}$$ and for $$-ve$$ part is $$\Delta {t_2}.$$ The value of $$e$$ $${{\Delta {t_2} - \Delta {t_1}} \over {RC}}$$ will be _______.

The second order dynamic system $${{dX} \over {dt}} = PX + Qu,\,\,\,y = RX$$ has the matrices $$P,Q,$$ and $$R$$ as follows: $$P = \left[ {\matrix{ { - 1} & 1 \cr 0 & { - 3} \cr } } \right]\,\,Q = \left[ {\matrix{ 0 \cr 1 \cr } } \right]$$
$$R = \left[ {\matrix{ 0 & 1 \cr } } \right]$$ The system has the following controllability and observability properties:

The closed-loop transfer function of a system is $$T\left( s \right) = {4 \over {\left( {{s^2} + 0.4s + 4} \right)}}.$$ The steady state error due to unit step input is ________

A system with the open loop transfer function $$G\left( s \right) = {K \over {s\left( {s + 2} \right)\left( {{s^2} + 2s + 2} \right)}}$$ is connected in a negative feedback configuration with a feedback gain of unity. For the closed loop system to be marginally stable, the value of $$K$$ is ________.

For the transfer function $$G\left( s \right) = {{5\left( {s + 4} \right)} \over {s\left( {s + 0.25} \right)\left( {{s^2} + 4s + 25} \right)}}.$$ The values of the constant gain term and the highest corner frequency of the Bode plot respectively are

The state transition matrix for the system $$\left[ {\matrix{ {\mathop {{x_1}}\limits^ \bullet } \cr {\mathop {{x_2}}\limits^ \bullet } \cr } } \right] = \left[ {\matrix{ 1 & 0 \cr 1 & 1 \cr } } \right]\left[ {\matrix{ {{x_1}} \cr {{x_2}} \cr } } \right] + \left[ {\matrix{ 1 \cr 1 \cr } } \right]u$$ is

The $$SOP$$ (sum of products) from of a Boolean function is $$\sum \left( {0,1,3,7,11} \right),$$ where inputs are $$A,B,C,D$$ ($$A$$ is $$MSB$$, and $$D$$ is $$LSB$$). The equivalent minimized expression of the function is

A $$JK$$ flip flop can be implemented by $$T$$ flip flops. Identify the correct implementation.

In an $$8085$$ microprocessor, the following program is executed

At the end of program, register $$A$$ contains

The switch SW shown in the circuit is kept at position ‘1’ for a long duration. At t = 0⁺, the switch is moved to position ‘2’ Assuming $$\left|V_{02}\right|\;>\;\left|V_{01}\right|$$, the voltage $$V_C\left(t\right)$$ across capacitor is

The total power dissipated in the circuit, show in the figure, is 1kW. The ideal voltmeter, across the load, reads 200 V. The value of X_L is _________.

The voltage across the capacitor, as sown in the figure, is expressed as $$$V_c\left(t\right)=A_1\sin\left(\omega_1t-\theta_1\right)+A_2\sin\left(\omega_2t-\theta_2\right)$$$ The value of A₁ and A₂ respectively, are

Two identical coupled inductors are connected in series. The measured inductances for the two possible series connections are 380 μH and 240 μH. Their mutual inductance in μH is ________.

Suppose that resistors $${R_1}$$ ܴand $${R_2}$$ ܴare connected in parallel to give an equivalent resistor $$R.$$ If resistors ܴ$${R_1}$$ and $${R_2}$$ ܴ have tolerance of $$1$$% each, the equivalent resistor ܴ$$R$$ for resistors ܴ$${R_1}$$$$=300$$ $$\Omega $$ and ܴ$${R_2} = 200\Omega $$ will have tolerance of

The saw-tooth voltage waveform shown in the figure is fed to a moving iron voltmeter. Its reading would be close to _______.

Two ammeters $$X$$ and $$Y$$ have resistances of $$1.2$$ $$\Omega $$ and $$1.5$$ $$\Omega $$ respectively and they give full-scale deflection with $$150$$ $$mA$$ and $$250$$ $$mA$$ respectively. The ranges have been extended by connecting shunts so as to give full scale deflection with $$15$$ $$A.$$ The ammeters along with shunts are connected in parallel and then placed in a circuit in which the total current flowing is $$15A.$$ The current in amperes indicated in ammeter $$X$$ is __________.

While measuring power of a three-phase balanced load by the two-wattmeter method, the readings are $$100$$ $$W$$ and $$250$$ $$W$$. The power factor of the load is ___________.

A $$20$$-pole alternator is having $$180$$ identical stator slots with $$6$$ conductors in each slot. All the coils of a phase are in series. If the coils are connected to realize single-phase winding, the generated voltage is $${V_1}.$$ If the coils are reconnected to realize three-phase star-connected winding, the generated phase voltage is $${V_ 2}.$$ Assuming full pitch, single-layer winding, the ratio $${V_1}/{V_2}$$ is

There are two generators in a power system. No-load frequencies of the generators are $$51.5$$ $$Hz$$ and $$51$$ $$Hz,$$ respectively, and both are having droop constant of $$1$$ $$Hz/MW.$$ Total load in the system is $$2.5$$ $$MW.$$ Assuming that the generators are operating under their respective droop characteristics, the frequency of the power system in $$Hz$$ in the steady state is ____________.

A synchronous generator is connected to an infinite bus with excitation voltage $${E_f} = 1.3\,pu.$$ The generator has a synchronous reactance of $$1.1$$ $$pu$$ and is delivering real power $$(P)$$ of $$0.6$$ $$pu$$ to the bus. Assume the infinite bus voltage to be $$1.0$$ $$pu.$$ Neglect stator resistance. The reactive power $$(Q)$$ in $$pu$$ supplied by the generator to the bus under this condition is ____________.

For a single phase, two winding transformer, the supply frequency and voltage are both increased by 10%. The percentage changes in the hysteresis loss and eddy current loss, respectively are

A 250 V dc shunt machine has armature circuit resistance of 0.6 $$\Omega$$ and field circuit resistance of 125 $$\Omega$$. The machine is connected to 250 V supply mains. The motor is operated as a generator and then as a motor separately. The line current of the machine in both the cases is 50 A. The ratio of the speed as a generator to the speed as a motor is ____________.

Assuming an ideal transformer, The Thevenin's equivalent voltage and impedance as seen from the terminals x and y for the circuit in figure are

A single phase, 50 kVA, 1000 V/100 V two winding transformer is connected as an autotransformer as shown in the figure. The kVA rating of the autotransformer is _________.

In a constant V/f control of induction motor, the ratio V/f is maintained constant from 0 to base frequency, where V is the voltage applied to the motor at fundamental frequency f. Which of the following statements relating to low frequency operation of the motor is TRUE?

A three-phase, 4-pole, self excited induction generator is feeding power to a load at a frequency $$f_1$$. If the load is partially removed, the frequency becomes $$f_2$$. If the speed of the generator is maintained at 1500 rpm in both the cases, then

A three-phase slip-ring induction motor, provided with a commutator winding, is shown in the figure. The motor rotates in clockwise direction when the rotor windings are closed. If the rotor winding is open circuited and the system is made to run at rotational speed f_r with the help of prime-mover in anti-clockwise direction, then the frequency of voltage across slip rings is f₁ and frequency of voltage across commutator brushes is f₂. The values of f₁ and f₂ respectively are

A parallel plate capacitor consisting two dielectric materials is shown in the figure. The middle dielectric slab is place symmetrically with respect to the plates. If the potential difference between one of the plates and the nearest surface of dielectric interface is 2 Volts, then the ratio $$\varepsilon_1\;:\;\varepsilon_2$$ is

The magnitude of magnetic flux density ($$\overrightarrow B$$) at a point having normal distance d meters from an infinitely extended wire carrying current of I A is $$\frac{\mu_0I}{2\mathrm{πd}}$$ (in SI units). An infinitely extended wire is laid along the x-axis and is carrying current of 4 A in the +ve x direction. Another infinitely extended wire is laid along the y-axis and is carrying 2 A current in the +ve y direction. μ₀ is permeability of free space. Assume $$\widehat i,\;\widehat j,\;\widehat k$$ to be unit vectors along x, y and z axes respectively. Assuming right handed coordinate system, magnetic field intensity, $$\overrightarrow H$$ at coordinate (2,1,0) will be

All the values of the multi valued complex function $${1^i},$$ where $$i = \sqrt { - 1} $$ are

Which one of the following statements is true for all real symmetric matrices?

Minimum of the real valued function $$f\left( x \right) = {\left( {x - 1} \right)^{2/3}}$$ occurs at $$x$$ equal to

To evaluate the double integral $$\int\limits_0^8 {\left( {\int\limits_{y/2}^{\left( {y/2} \right) + 1} {\left( {{{2x - y} \over 2}} \right)dx} } \right)dy,\,\,} $$ we make the substitution $$u = \left( {{{2x - y} \over 2}} \right)$$ and $$v = {y \over 2}.$$ The integral will reduce to

The minimum value of the function $$f\left( x \right) = {x^3} - 3{x^2} - 24x + 100$$ in the interval $$\left[ { - 3,3} \right]$$ is

Consider a die with the property that the probability of a face with $$'n'$$ dots showing up is proportional to $$'n'.$$ The probability of the face with three dots showing up is _________.

Let $$X$$ be a random variable with probability density function $$f\left( x \right) = \left\{ {\matrix{ {0.2} & {for\,\left| x \right| \le 1} \cr {0.1} & {for\,1 < \left| x \right| \le 4} \cr 0 & {otherwise} \cr } } \right.$$

The probability $$P\left( {0.5 < x < 5} \right)$$ is _________.

Consider the differential equation $${x^2}{{{d^2}y} \over {d{x^2}}} + x{{dy} \over {dx}} - y = 0.\,\,$$ Which of the following is a solution to this differential equation for $$x > 0?$$

The $$SCR$$ in the circuit shown has a latching current of $$40$$ $$mA.$$ A gate pulse of $$50$$ $$\mu s$$ is applied to the $$SCR$$. The maximum value of $$R$$ in $$\Omega $$ to ensure successful firing of the $$SCR$$ is ____________.

A fully controlled converter bridge feeds a highly inductive load with ripple free load current. The input supply $$\left( {{V_s}} \right)$$ to the bridge is a sinusoidal source. Triggering angle of the bridge converter is $$\,\alpha = {30^0}.$$ The input power factor of the bridge is ____________.

A step-up chopper is used to feed a load at $$400$$ $$V$$ $$dc$$ from a $$250$$ $$V$$ $$dc$$ source. The inductor current is continuous. If the ‘off’ time of the switch is $$20\,\,\mu s,$$ the switching frequency of the chopper in $$kHz$$ is ________.

A single-phase $$SCR$$ based $$ac$$ regulator is feeding power to a load consisting of $$5\,\,\Omega $$ resistance and $$16$$ $$mH$$ inductance. The input supply is $$230$$ $$V,$$ $$50$$ $$Hz$$ $$ac.$$ The maximum firing angle at which the voltage across the device becomes zero all throughout and the $$rms$$ value of current through $$SCR,$$ under this operating condition, are

A three phase star-connected load is drawing power at a voltage of 0.9 pu and 0.8 power factor lagging. The three phase base power and base current are 100 MVA and 437.38 A respectively. The line-to-line load voltage in kV is __________.

A three phase, $$100$$ $$MVA,$$ $$25$$ $$kV$$ generator has solidly grounded neutral. The positive, negative, and the zero sequence reactance's of the generator are $$0.2$$ $$pu$$, $$0.2$$ $$pu$$, and 0.05 $$pu,$$ respectively, at the machine base quantities. If a bolted single phase to ground fault occurs at the terminal of the unloaded generator, the fault current in amperes immediately after the fault is __________

Shunt reactors are sometimes used in high voltage transmission systems to

A single phase induction motor draws $$12MW$$ power at $$0.6$$ lagging power. A capacitor is connected in parallel to the motor to improve the power factor of the combination of motor and capacitor to $$0.8$$ lagging. Assuming that the real and reactive power drawn by the motor remains same as before, the reactive power delivered by the capacitor in MVAR is _______ .

The horizontally placed conductors of a single phase line operating at $$50$$ $$Hz$$ are having outside diameter of $$1.6$$ cm, and the spacing between centers of the conductors is $$6$$ m. The permittivity of free space is $$8.854 \times {10^{ - 12}}\,\,F/m.$$ The capacitance to ground per kilometer of each line is

Consider an LTI system with impulse response $$h\left(t\right)=e^{-5t}u\left(t\right)$$ . If the output of the system is $$y\left(t\right)=e^{-3t}u\left(t\right)-e^{-5t}u\left(t\right)$$ then the input, x(t), is given by

Consider an LTI system with transfer function $$H\left(s\right)=\frac1{s\left(s+4\right)}$$.If the input to the system is cos(3t) and the steady state output is $$A\sin\left(3t+\alpha\right)$$, then the value of A is

A 10 kHz even-symmetric square wave is passed through a bandpass filter with centre frequency at 30 kHz and 3 dB passband of 6 kHz. The filter output is

An input signal x(t) = 2 + 5sin(100$$\mathrm\pi$$t) is sampled with a sampling frequency of 400 Hz and applied to the system whose transfer function is represented by $$$\frac{Y\left(z\right)}{X\left(z\right)}=\frac1N\left[\frac{1-z^{-N}}{1-z^{-1}}\right]$$$ where, N represents the number of samples per cycle. The output y(n) of the system under steady state is

A discrete system is represented by the difference equation $$$\begin{bmatrix}X_1\left(k+1\right)\\X_2\left(k+2\right)\end{bmatrix}=\begin{bmatrix}a&a-1\\a+1&a\end{bmatrix}\begin{bmatrix}X_1\left(k\right)\\X_2\left(k\right)\end{bmatrix}$$$ It has initial condition $$X_1\left(0\right)=1;\;X_2\left(0\right)=0$$. The pole location of the system for a = 1, are