Answer / bharth reddy

i choose this branch because it is ever green subject.In this field we have numerous jobs.We can work both in hardware and software.Now-a-days every one is carrying cell phones even though they don't have money.This can shows how the electronics has became part in our daily life.We can't imagine our life with out electronics.Starting from home to even in office and outside also we are using.In modern days almost every thing is built with integrated circuits,microprocessors,transistors.I want to know how they work and built. So i have choose this branch 

Answer / ram reddy

We are supposed to do anying iN the using electronic and digital acquipments.without this no world can be developed so I provedly say ece is best branch

Answer / remark

Because I am amazed with the advanced development of Technologies nowadays. I enjoy learning and appreciate those knowledge that I gained in the Field of ECE

Answer / rahul srivastava

Since we get acquainted with immense knowledge of both the IT and Communications in it.

Answer / karthik

I have strong passion for coding and would like to work in tha same field.since one should do the work what they enjoy..well comming to the point of ece it is a professional cource if soft ware wanted to develop some thing then it must neec hardware microprocessors,microchipsetc
There are some chanses of getting down of software field because upcoming generation is automated..but hardware will not becz we r the 1 who creat device......the lords of ece

Answer / ahmed

bcz nothing in this world without electronics and i wan 2 do
work 4r ds world

Answer / timmappa

1.those who have the logical sense,then choose this one.

2.u have a enjoy or hard work person then select this .

Answer / vinothkumar

ECE branch i chosed..bcoz to
knw about both electrnic
devices and how to
communication processed, al
include in ece..i like many
subjects antena,tlw,DIP..

Answer / joydeb karmakar

i think that there is nothing with out electronics and wireless communication throughout the world.

Answer / virus

its a big time pass..full on entertainment..i haven't chosen ece yet..

how to know working functions of ICs using simple circuits

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0 Answers   NSN,

Explain what are the advantages of using a voltage follower amplifier?

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Sunday, April 25, 2010 BSNL TTA EXAM Control Systems BSNL TTA EXAM Control Systems 1. An open loop control system has its (a) control action independent of the output or desired quantity (b) controlling action, depending upon human judgment (c) internal system changes automatically taken care of  (d) both (a) and (b) (e) all (a),(b) and (c) 2. A servo system must have (a) feedback system (b) power amplifier to amplify error (c) capacity to control position or its derivative  (d) all of these (e) none of these 3. The major disadvantage of a feedback system may be  Inaccuracy (b) inefficiency (c) Unreliability (d) instability (e) Insensitivity 4. Properties of a transfer function (a) It is ratio of two polynomials is S and assumes zero initial conditions (b) It depends on system elements and not input and output of the system (c) Coefficients of the powers of S in denominator and numerator are all real constant. The order of denominator is usually greater than or equal to the order of numerator (d) All of these (e) It is a function which transfer one physical system into another physical system. 5. The classical analogous of a simple lever is (a) Capacitor bridge (b) transformer (c) mutual inductor (d) either of these 6. Two blocks G1(s) and G2(s) can be cascaded to get resultant transfer function as (a) G1(s) + G2(s) (b) G1(s) / G2(s) (c) G1(s) G2(s) (d) 1+G1(s) G2(s) (e) 1-G1(s)G2(s) (f) two blocks cannot be cascade 7. The principles of homogeneity and super position can be applied to  linear time invariant system (b) non-linear time invariant system (c) digital control system (d) both (a) and (b) 8. Pick up the nonlinear system (a) automatic voltage regulator (b) d.c. servomotor with high field excitation (c) temperature control of a furnaces using thermistor (d) speed control using SCR (e) all of these 9. Signal flow graph (SFG) is a (a) polar graph (b) semi log graph (c) log log graph  (d) a special type of graph for analyzing modem control system (e) a topological representation of a set of differential equations 10. Disadvantages of magnetic amplifier (a) time lag, less flexible, non-sinusoidal waveform (b) low power consumption and isolation of the active circuit (c) saturation of the core (d) all of these 11. Pick up false statement regarding magnetic amplifiers (a) The gate coil of an ideal magnetic amplifier has either zero or infinite inductance (b) Resistance of control and gate winding is very small (c) Magnetic amplifier gas dropping load characteristics (d) Magnetic amplifiers are not used to control the speed of d.c. shunt motor (e) Magnetic amplifiers can be used in automatic control of electric drivers of higher rating. 12. High power amplification is achieved by using (a) push pull amplifier (b) amplidyne (c) magnetic amplifier (d) DC amplifier (e) D.C. generator 13. Pick up false statement regarding servomotors (a) The d.c. servomotors are lighter than equivalent a.c. servomotors (b) The d.c. servomotors develops higher starting and reversing torque than equivalent a.c. servomotor. (c) A drag cup a.c. servomotor has one windings on stator and other on rotor (d) Output power of servomotors varies from 1/20 W to 100 W 14. To reduce steady state error (a) decrease natural frequency (b) decrease damping (c) increase damped frequency (d) increase time constant (f) increase gain constant of the system 15. A good factor for Mp should be (a) less than 1 (b) lying between 1.1 and 1.5 (c) more than 2.2 (d) zero (e) infinity 16. Pick up false statement. Routh-Hurwitz criterion (a) is used for determining stability of a system (b) is an algebraic procedure (c) gives the exact location of roots of the characteristic equation (d) does not indicate relative degree of stability or instability 17. Which of the following is the time domain method of determining stability of a control system (a) Bode plot (b) Nyquist plot (c) Nicholos chart (d) Routh-Hurwitz array (e) Constant M and (fy) locus (f) Root locus technique 18. The technique which gives transient response quickly as well as stability information is (a) Nyquist plot (b) Routh-Hurwitz criteria (c) Bode plot (d) Root locus plot (e) Nichols plot 19. The bandwidth can be increased by use of (a) phase lag network (b) phase lead network (c) both (a) and (b) in cascade (d) both (a) and (b) in parallel (e) none of these 20. Nyquist plot is drawn on (a) semi log graph paper (b) log log graph paper (c) polar graph paper (d) centimeter graph paper 21. If the gain margin is positive and the phase margin is negative the system is (a) stable (b) unstable (c) indeterminist 22. The Bode plot is applicable to (a) all phase network (b) minimum phase network (c) maximum phase network (d) lag lead network (e) none of these 23. The valid relation between setting time ts and rise time tr is (a) tr>ts (b) ts>tr (c) ts=tr (d) none of these 24. As a root moves further away from imaginary axis the stability (a) increases (b) decreases (c) not affected (d) none of these 25. Flat frequency response means that the magnitude ratio of output to input over the bandwidth is (a) variable (b) zero (c) constant (d) none of above 26. How many octaves are between 200 Hz and 800 Hz (a) Two octave (b) One octave (c) Four octave (d) None of above 27. Human system can be considered as (a) open loop system (b) close loop system with single feedback (c) close loop system with multivariable feedback (d) none of these 28. In a feedback system the transient response (a) Decays at constant rate (b) gets magnified (c) decays slowly (d) decays more quickly 29. Transfer function of a system is used to calculate (a) the steady state gain (b) the main constant (c) the order of system (d) the output for any given input (e) all of the above 30. Transfer function of a system is defined as the ratio of output to input in (a) Laplace transform (b) Z-transform (c) Fourier transform (d) Simple algebraic form 31. Introduction of feedback decreases the effect of (a) disturbances (b) noise signals (c) error signals (d) all the above 32. The system response of a system can be best tested with (a) unit impulse input signal (b) ramp input signal (c) sinusoidal input signal (d) exponentially decaying input signal 33. Which of the following is a closed loop system (a) electric switch (b) car starter (c) de generator (d) auto-pilot for an aircraft 34. Which of the following is used as an error detector (a) potentiometer (b) field controlled ac motor (c) amplidyne (d) armature controlled ac motor 35. The break away point of root loci are (a) open loop poles (b) closed loop poles (c) open loop zeros (d) closed loop zeros 36. Noise in a control system can be kept low by (a) reducing the bandwidth (b) attenuating such frequencies at which external signals get coupled into the system (c) both (a) and (b) (d) none of these 37. Main cause of absolute instability in the control system is (a) parameters of controlling system (b) parameters of controlled system (c) parameters of feedback system (d) error detector where the two signals are compared 38. Basically a controller is (a) a amplifier (b) a clipper (c) a comparator (d) a summer 39. A system with gain margin close to unity or a phase margin close to zero is (a) highly stable (b) highly oscillatory (c) relatively stable (d) none of these 40. Which of following elements is not used in an automatic control system (a) sensor (b) error detector (c) oscillator (d) final control element 41. AC systems are usually preferred to the DC systems in control applications because (a) AC systems are cheaper (b) AC systems are more stable (c) AC systems have better performance characteristics and smaller in size (d) all of these 42. A system has the transfer function (1-s)/(1+s); It is known as (a) low pass system (b) high pass system (c) all pass system (d) none of the above 43. In control systems, excessive bandwidth should be avoided because (a) noise is proportional to bandwidth (b) it leads to low relative stability (c) it leads to slow speed of response (d) none of these 44. In most systems, an increase in gain leads to (a) larger damping ratio (b) smaller damping ratio (c) constant damping ratio (d) none of these 45. A step function is applied to the input of a system and output is of the form y = t, the system is (a) stable (b) unstable (c) not necessarily stable (d) conditionally stable 46. Which of the following can be magnified by magnetic amplifier (a) voltage (b) current (c) power (d) none of above 47. The inductance is not used in lag network because of (a) big size (b) time delay and hysteresis losses (c) high reactance (d) none of these 48. Saturation in a stable control system can cause (a) conditional stability (b) over damping (c) low level oscillations (d) high level oscillations 49. Excessive noise in control systems can cause (a) reduction in bandwidth (b) reduction in gain (c) saturation in amplifying stages

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What is meant a parallel inverter?

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at the time of doing second year which course can we study..? and where we should study...?

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Why Visual Basic is referred to as "Front End Tool"?

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why rx level is negative in telecom?

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What is the basis for classifying a material as a conductor, semiconductor, or a dielectric? Define what is the conductivity of perfect dielectric?

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You Are Fresher?Wana Start Your Carrer In Intelli Group Hyderabad Only possible via Niteo IT Consultant...

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I want previous rrb enteranse exam papers in junior engineer(Signal/Tele/c&w). please send that papers to my id dkg_unnao@yahoo.com

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what is the operation of logic gates when no input is applied

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