# All India Electronics and Communication Engineering (ECE) Group

## The line-to-line voltage of 3-phase T-type inverter has …….. levels?

 Akshay Nair answered  •  2 hours ago

Line-to-Line Voltage Levels of 3-Phase T-Type Inverter:

Explanation:

1. Phase Voltage Levels:
• Phase voltage refers to the voltage between any one phase and neutral in a 3-phase system.
• In a T-type inverter, the phase voltage levels are determined by the switching pattern of the inverter.
• The phase voltage lev... more

2. Line-to-Line Voltage Levels:
• Line-to-line voltage refers to the voltage between two phases in a 3-phase system.
• In a T-type inverter, the line-to-line voltage levels are determined by the combination of phase voltages based on the inverter topology.
• The line-to-line voltage levels can be calculated using the phase voltage levels and the phase shift between the phases.

3. Levels of Line-to-Line Voltage:
• The line-to-line voltage of a 3-phase T-type inverter can have different levels based on the switching states of the inverter.
• Common levels of line-to-line voltage include:
• Low voltage level - when only one leg of the inverter is active.
• Medium voltage level - when two legs of the inverter are active.
• High voltage level - when all three legs of the inverter are active.

• The levels of line-to-line voltage determine the output voltage of the inverter and impact the overall performance of the system.

## A control system is said to be robust whena)it has low sensitivitiesb)it is stable over a wide range of parameter variationc)both (a) and (b)d)neither (a) nor (b)Correct answer is option 'C'. Can you explain this answer?

Explanation of a robust control system:

- Low sensitivities: A robust control system should have low sensitivities to uncertainties and disturbances. This means that even if there are slight variations or disturbances in the system, the control system should be able to maintain stability and performance without significant changes. Low sensitivities ensure that the system can effectively handle variations in parameters without compromising its operation.

- Stable over a wide range of parameter variation: Another important aspect of a robust control system is its ability to remain stable over a wide range of parameter variations. This means that the system should be able to maintain its stability and performance even when there are significant changes in the parameters or operating conditions. A robust control system should be able to adapt to different conditions and still perform optimally.

- Both (a) and (b): Therefore, a robust control system is one that not only has low sensitivities to uncertainties and disturbances but also remains stable over a wide range of parameter variations. By combining these two characteristics, a robust control system can effectively handle uncertainties and variations in the system, ensuring reliable and consistent performance.

## Logical expression (A+B) (A+C) is equal toa)A + B + Cb)A + B.Cc)A.B + A.Cd)A.B.CCorrect answer is option 'B'. Can you explain this answer?

 Saanvi Joshi answered  •  15 hours ago
Explanation:

Given Expression: (A + B) (A + C)

Expanding the expression:
(A + B) (A + C) = A(A + C) + B(A + C)
= A.A + A.C + B.A + B.C
= A + AC + BA + BC
= A + AC + AB + BC
= A(1 + C) + B(C)
= A + AC + BC

Final Simplified Expression: A + B.C
Therefore, the logical expression (A + B) (A + C) is equal to
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## Air craft of Jet Airways at Ahmedabad airport arrive according to a Poisson process at a rate of 12 per hour. All aircraft are handled by one air traffic controller. If the controller takes a 2 – minute coffee break, what is the probability that he will miss one or more arriving aircraft?a)0.33b)0.44c)0.55d)0.66Correct answer is option 'A'. Can you explain this answer?

 Jayant Chopra answered  •  23 hours ago
Understanding the Problem:
The arrival of aircraft at Jet Airways follows a Poisson process with a rate of 12 per hour. The air traffic controller takes a 2-minute coffee break. We need to find the probability that he will miss one or more arriving aircraft during this break.

Calculating the Arrival Rate:
Given that aircraft arrive at a rate of 12 per hour, we ca
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## The power spectral density of deterministic signal is given by [sin(f)/f]2. where 'f' is frequency. The auto-correlation function of the signal in the time domain is -a)a sine pulseb)a delta functionc)a triangular pulsed)a rectangular pulseCorrect answer is option 'C'. Can you explain this answer?

 Rahul Ahuja answered  •  3 days ago
Explanation:

Power Spectral Density (PSD) given by [sin(f)/f]^2:
- The power spectral density of a deterministic signal is given by [sin(f)/f]^2.
- This means that the frequency content of the signal is proportional to the square of the sine function divided by the frequency.

Auto-correlation function in the time domain:
- The auto-correlat
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## Assertion (A): In India we use CCIR-B standardReason (R): Video signals are frequency modulated.a)Both A and R are correct and R is correct explanation of Ab)Both A and R are correct but R is not correct explanation of Ac)A is correct but R is wrongd)A is wrong but R is correctCorrect answer is option 'C'. Can you explain this answer?

 Rahul Ahuja answered  •  3 days ago
Explanation:

Assertion (A):
- The statement is correct. In India, the CCIR-B standard is commonly used for television broadcasting.

Reason (R):
- The reason provided is incorrect. Video signals are actually amplitude modulated, not frequency modulated.
Therefore, option 'C' is the correct answer as Assertion (A) is correct but the Reason (
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## Consider a silicon n+p junction solar cell with a 1 cm2 surface area and NA = 1015/cm3. Calculate IL (light current) and Voc (open circuit voltage).Assume Dn = 35cm2sec-1, τn = 2.57 μsec and GL = 2.7 × 1019 cm3 sec-1, VT = 25.86 x 10-3 V, ni = 1.5 x 1010 cm3. a)IL = 1.33 x 10-10 A, VOC = 0.505 Vb)IL = 40.95 mA, VOC​ = 0.505 Vc)IL = 1.33 x 10-10 A, VOC​ = 0.852 Vd)IL = 40.95 mA, VOC​ = 0.852 VCorrect answer is option 'B'. Can you explain this answer?

 Bhavya Singh answered  •  3 days ago
Calculating IL (light current) and Voc (open circuit voltage)
1. Calculating IL (light current):
Given parameters:
- NA = 10^15/cm^3
- Dn = 35 cm^2/sec
- τn = 2.57 μsec
- GL = 2.7 x 10^19 cm^3 sec^-1
- VT = 25.86 x 10^-3 V
- ni = 1.5 x 10^10 cm^3
Using the formula for IL:
IL = q * GL * τn * NA * VT / (2 * Dn)
Substitut
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## Let E = (-200ax + 30ay + 70az) cos 104 t V/m at point 'P which lies on the surface of a perfect conductor P (3, -4,1). If a material adjacent to the conductor has ∈r = 5, μf = 0, σ = 0, then surface charge density on the conductor surface at Pa)±5.2 cos2 10t b)± 3.48 cos 102tc)± 5.2 cos 104td)± 3.48 cos 104tCorrect answer is option 'D'. Can you explain this answer?

 Bhavya Singh answered  •  3 days ago
Given Information:
- Electric field E = (-200ax+ 30ay + 70az) cos 104t V/m at point P (3, -4,1)
- Point P lies on the surface of a perfect conductor
- Material adjacent to the conductor has r = 5, f = 0, θ = 0

Surface Charge Density Calculation:
- The surface charge density on a perfect conductor is given by σ = n * E
- Where n is the u
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## Amplitude distortion is due to ___________a)Shift in Q-pointb)Change in inputc)Linear amplificationd)Small input signalCorrect answer is option 'A'. Can you explain this answer?

 Chhavi Gupta answered  •  4 days ago
Amplitude distortion is due to Shift in Q-point
- Shift in Q-point:
When the Q-point of a transistor amplifier shifts from its ideal position, it can lead to amplitude distortion in the output signal. The Q-point is the operating point of the transistor where it remains in active region for amplification. If the Q-point shifts due to factors like temperature variations, component
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## The nominal quiescent collector current of a transistor is 1.2 mA. If the range of β for this transistor is 80 ≤ β ≤ 120 and if the quiescent collector current changes by +-10 percent, the range in value for rπ isa)1.73 kΩ < rπ < 2.59 kΩb)1.93 kΩ < rπ <  2.59 kΩc)1.73 kΩ < rπ < 2.59 kΩd)1.56 kΩ  < rπ <  2.88 kΩCorrect answer is option 'D'. Can you explain this answer?

 Chhavi Gupta answered  •  4 days ago
Given Data:
Nominal quiescent collector current = 1.2 mA
Range of β for the transistor = 80 to 120
Change in quiescent collector current = ±10%

Calculation:
1. Calculate the range of quiescent collector current:
Minimum quiescent collector current = 1.2 mA - 10% of 1.2 mA
= 1.2 mA - 0.12 mA
= 1.08 mA
Maximum quiescent collector curre
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## Which one of the following is a true statementa)1/2 (bxy + byx ) = rb)1/2 (bxy + byx ) < rc)1/2 (bxy + byx ) > rd)none of theseCorrect answer is option 'C'. Can you explain this answer?

 Pranav Bhatia answered  •  4 days ago
Explanation:

Given expression:
1/2 (bxy+ byx)

Simplifying the expression:
1/2 (bxy+ byx) = 1/2 * bxy + 1/2 * byx
= bxy/2 + byx/2

Comparing with the given options:
Option a) 1/2 (bxy+ byx) = r is incorrect
Option b) 1/2 (bxy+ byx) r is incorrect
Option c) 1/2 (bxy+ byx) r is correct
Option d) none of the
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## The minterm expansion of f (P, Q, R) = PQ + QR̅ + PR̅ isa)m2 + m4 + m6 + m7b)m0 + m1 + m6 + m7c)m2 + m3 + m4 + m5d)m0 + m1 + m3 + m7Correct answer is option 'A'. Can you explain this answer?

 Yash Khurana answered  •  4 days ago
Explanation:

Minterms:
- In Boolean algebra, a minterm is a product term that contains all the variables of the function in either their true or complemented form.
- For a function of three variables P, Q, and R, there are 2^3 = 8 possible minterms (m0 to m7).

Minterm Expansion:
- The given function f(P, Q, R) = PQ + QR + PR can be expresse
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## In TV signals colour burst is useda)to maintain colour sequenceb)to ensure I and Q phase correctlyc)to synchronise coloursd)for interlacing of horizontal linesCorrect answer is option 'B'. Can you explain this answer?

 Yash Khurana answered  •  4 days ago
Explanation:
Colour Burst in TV Signals
- The colour burst is a signal used in television broadcasting to ensure that the I and Q phases are correct.
- It is a reference signal that is sent during the horizontal blanking period of the video signal.
- The colour burst signal contains information about the phase and amplitude of the colour carrier signal.
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## The absorption spectrum of O2 shows vibrational structure which becomes a continuous at 56876cm-¹; the upper electronic state dissociation into one ground state atom and one excited atom. Estimate the dissociation energy of g... more

 Devang Choudhary answered  •  5 days ago
Estimating Dissociation Energy of Ground State O2
Estimating the Dissociation Energy requires understanding the absorption spectrum of O2 and the vibrational structure it exhibits.

Vibrational Structure of O2 Absorption Spectrum
- The absorption spectrum of O2 shows vibrational structure until it becomes continuous at 56876 cm-1.
- This vibrational structur
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## The total efficiency of an injection laser with a GaAs active region is 18%. The voltage applied to the device is 2.5 V and the bandgap energy for GaAs is 1.43 eV. The external power efficiency of the device isa)5%b)10%c)15%d)20%Correct answer is option 'B'. Can you explain this answer?

 Gautam Rao answered  •  5 days ago
Given data:
- Total efficiency of injection laser = 18%
- Voltage applied to the device = 2.5 V
- Bandgap energy for GaAs = 1.43 eV

Calculating External Power Efficiency:
- The total efficiency of the laser can be broken down into internal quantum efficiency (ηi) and external power efficiency (ηext) as follows:
Total efficiency = ηi * ηext
-
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## An amplier has three stages te1=150k?

Amplifier with Three Stages (Te1=150k)

Introduction:
An amplifier with three stages refers to a circuit with three separate amplification stages that work together to increase the strength of an input signal. In this case, Te1=150k indicates the transconductance of the first stage in the amplifier, which is a crucial parameter for determining the overall performance o
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