Measurement technology textbook problems

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The discussion covers various measurement technology problems, including the Wheatstone bridge circuit and its balance conditions, the Aron connection for three-phase power measurement, and the V-A method for resistance measurement. It emphasizes the importance of understanding the operating principles and relationships between mechanical and electrical parameters. The accuracy of different voltmeters for measuring DC voltage is also analyzed, with calculations suggested to determine the most precise instrument. Additionally, the impact of amplitude differences on waveform analysis is raised, highlighting the complexities in interpreting oscilloscope data. The conversation underscores the need for focused problem-solving in measurement technology.
NotFivehead
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Homework Statement
Measurement technology problems
Relevant Equations
There is no single solution because there are multiple problems
1) Describe the Wheatstone bridge circuit and its condition for balance

2) What is shown in the figure? Explain its operating principle. Derive the relationship between the mechanical and electrical parameters.

3) We are measuring three-phase power using the Aron connection (2-wattmeter method). The power meter specifications are: I(n) = 3 A, U(n) = 300 V, cosφ(n) = 1, scale range = 150°, α₁ = 60°, α₂ = 72°, p(0) = 0,2.
a) What is the application condition for this connection method?
b) What is the active power consumption of the load?
c) What are the reactive and apparent power consumptions of the load?

4) We are measuring resistance using the V-A method. The voltmeter's measurement range is 50 V, and the ammeter's is 1,5 A. The measured voltage is 24 V, and the measured current is 0,8 A. The voltmeter's internal resistance is characterized by 2000 Ω/V, and the ammeter's internal resistance is 0,5 Ω. Both instruments have an accuracy class of 0,5.
a) Determine the measured value of the resistance!
b) Specify the circuit configuration that results in smaller systematic measurement error! Justify your choice! What causes this error?

5) We are measuring a DC voltage of U(measured) = 3 V using the following instruments:
- Deprez voltmeter, accuracy class h(accuracy class) = 0.5, measurement range U(measurement range) = 10 V
- Electrodynamic voltmeter, accuracy class h(accuracy class) = 1.5, measurement range U(measurement range) = 5 V
- 3½-digit digital voltmeter, error ±(0.2% FS + 2D), measurement range U(measurement range) = 20 V
Which instrument allows the most accurate measurement? Justify your choice with calculations!

6) The following waveform was observed on the oscilloscope screen:
a) What quantities can be measured based on the displayed waveform?
b) What is the phase difference between the two compared sinusoidal voltages?

My notes are in the PDF. I had to translate things from Hungarian, sorry in advance!
 

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I think that you have received a DM by now from the Mentors mentioning that we usually prefer just one problem per thread. It is hard for most folks to respond to so many questions in one thread.

Having said that, I'll try to respond to one of the problems:
NotFivehead said:
Homework Statement: Measurement technology problems
Relevant Equations: There is no single solution because there are multiple problems

6) The following waveform was observed on the oscilloscope screen:
a) What quantities can be measured based on the displayed waveform?
b) What is the phase difference between the two compared sinusoidal voltages?
1750880236940.webp

The problem statement doesn't seem to say that the amplitudes of the two sinusoids are the same. What effect would different amplitudes have on the displayed figure?
 
Thread 'Correct statement about size of wire to produce larger extension'
The answer is (B) but I don't really understand why. Based on formula of Young Modulus: $$x=\frac{FL}{AE}$$ The second wire made of the same material so it means they have same Young Modulus. Larger extension means larger value of ##x## so to get larger value of ##x## we can increase ##F## and ##L## and decrease ##A## I am not sure whether there is change in ##F## for first and second wire so I will just assume ##F## does not change. It leaves (B) and (C) as possible options so why is (C)...

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