National Thermal Power Corporation

management Trainee

Electronics And Communication

• To obtain 10 mV resolution on 5 V range how many bit DAC is to be used..
• Why is LCD preferred to LED.
• How will 0.6973 be displayed on 10 V range of a 4 ½ digit multimeter.
• Which of the following cannot be used for an automatic feedback temp ctrl system thermocouple/thermometer/thermistor/IC sensor.
• Y(n)=X(-n+3) is an example of a linear/non linear and shift variant/invariant system.
• The falling body method is used to determine viscosity/humidity/?
• Which of these methods of viscosity measurement gives greatest accuracy falling body method/rotating cylinder method/both/?
• Some question on gas chromatography
• A device having a rotor with 3 Y-connected coils and a stator is likely to be a synchro/RVDT/control transformer/?
• In a twisted ring counter the initial count is 1000. after the 4th clock pulse its state will be?
• A 240 kHz signal is given into a 3 bit binary ripple counter. The lowest o/p freq obtainable is?
• For parity bit checking which of the following gates can be used XOR/NAND/OR/XNOR.
• Why is a BJT called so..
• Identify the expression for gauge factor of a strain gauge among the given options.
• In a semiconductor strain gauge as tensile strain is applied what changes take place in the n and p areas..
• How does a radioactive level gauging system work?
• A capacitive transducer measuring level works on the principle of change in distance between plates/change in dielectric strength/?
• For maximum power transfer in an AC circuit the condition to be satisfied is ZL+ZS=0/XL+XS=0/none of these/?where l and s refers to load and source respectively.
• Find the transfer function from a block diagram.
• Synchronous ctrs are preferred to asynchronous ctrs bcoz they are faster/glitches at the output can be avoided/both/none of these.
• The lissajous figure formed on an oscilloscope looks like the English figure of 8. if the vertical channel input is 1 kHz the horizontal input freq is?
• IE=IC for a transistor in saturation/cutoff/active/both saturation and active regions.
• Reproducibility of measurements is called accuracy/precision/linearity/none of these.
• Which of these is not strictly a static characteristic accuracy/precision/tolerance/linearity.
• The shunt coil in a Q meter has resistance of the order of m?/?/k?/..
• For measuring inductance of high Q coils the bridge used is Maxwell-wien/Schering/?
• Which of these measures inductance in terms of capacitance Maxwell and hay/Maxwell and Schering/hay and Schering/?
• In a flip-flop with preset and clear inputs both are applied simultaneously/clear is cleared when preset is applied/preset is cleared when clear is applied/?
• What happens when the RET instruction is encountered by 8085
• A 1024*8 memory chip needs how many address lines?
• What happens when the PUSH instruction is encountered by 8051.
• In FM relation between no of sidebands w.r.t. modulating freq
• Numerical on DPSK.
• A multiplexer accepts input data and provides one output all the time/one output at a time/many outputs at a time/many outputs all the time.
• Pulse modulation is essentially a process of multiplexing/?
• Wave shape is altered by clipper/clamper/voltage doubler/amplifier.
• 4 signals of frequencies 100,100,200 and 400 Hz are sampled at nyquist rate and sent through TDM on a channel.the bandwidth of the channel is?
• Superposition can be applied to a ckt with initial conditions/non-linear ckt/?
• Kelvin’s double bridge is used for the measurement of?
• Which of these is not an active transducer thermocouple/solar cell/RTD/none of these.
• Oscillator using positive feedback has gain of 0/?/undefined value/?
• Wien bridge oscillator should initially have closed loop gain >3/<3/=3/?
• Some question on gain margin and phase shift of a system.
• Fourier series expansion of even function has sine terms only/cosine terms only/no odd harmonics/?
• Full wave rectifier gives clean dc o/p/dc o/p with small ripple/positive half and inverted negative half of i/p as o/p.
• Which of these values of ? gives damped oscillations: 0/1/1.6/0.6
• For a transformer of ratio 1:a and excited by a source V with impedance Z1 and Z2 on the primary and secondary side value of a for maxmimum power transfer should be..
• Fourier transform of cos(?0t) is?
• At t=0 the step response of a 1st order system is?
• 555 can be used as a monostable/astable/freq dividing ckt/all of these.
• In a PT when the secondary is open ckted with the primary excited what will happen.
• If a system is marginally stable then the nature of oscillations will be?
• Linear encoders mostly use straight binary/BCD/gray code.
• For an accelerometer working in displacement mode the ratio of forcing freq to natural freq should be?

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