Resistance Measurement: Finding a Ditch w/ 4 Electrodes

In summary, resistance measurement is a technique used to find a ditch with 4 electrodes. It involves measuring the resistance of the ground using four electrodes placed in a specific pattern, typically in a straight line. This method can be used to locate ditches or other underground structures that may affect construction or other activities. By analyzing the resistance values, it is possible to determine the presence and depth of the ditch, providing valuable information for planning and decision-making.
  • #1
nicco35
9
0
Hello,
Could you help me with the homework, please...For the conventional resistance measurement used four electrodes: two current (A, B) into the country "deserts" and the current I between two measuring (M, N) is then measured voltage AU, resistivity, which is the goal of our measurement is determined according to Ohm's law; in its formula is needed to add a so-called. arrangements constant k, which depends on the distance of the individual electrodes. The calculated value is then referred to as "apparent resistivity" ρz, because it describes the whole "block" hemisphere, where penetrated current:

ρz = k * AU / I

Depth of this measurement is approximately 1/3 of the distance between the electrodes A and B. How far AB hypothetically you chose if you think that the resistance measurements would allow to determine the presence of a ditch.
 
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  • #2
The general subject of this post is "electrical ground probing" ( Described in http://www.reeve.com/Documents/Ground%20Testing%20R1-1.pdf)
However, the statement of the problem is unclear
Can you show a diagram?
What type of book poses this problem? - a geology book? a general physics book? an archaeology book?
 
  • #4
The depth of the ditch given? Is the width of the ditch given?
 
  • #5
He's going to archaeological research the castle, which
will be preceded by geophysical measurements. The challenge is also localization
said ditch. According to available information,
it is almost certain that trench was carved into the rock, its depth could be around 6 meters and width of 6-8 meters. We can assume that filling the trench extinct forms loamy - stony material with a share flushes cultural layers.
 
Last edited:
  • #6
If this is elementary algebra you would say 2 = (1/3) X and solve for X.

If this is an engineering course, you might have to use more equations.
 
  • #7
Please, help me..
 
  • #8
No, that is homework from high school
 
  • #9
Please, its depth is 6 meters and width 6-8 meters. How far AB hypothetically you chose if you think that the resistance measurements would allow to determine the presence of a ditch. Formula is ρz = k * AU / I. What am I substitute. Please, help me...
 
  • #10
You must reveal all the known information and perhaps other formulas.
Which values are known?
Is the voltage of the battery known? AU = voltage? = ?
Do you know a formula that tells the value of k as a function of the distance between the electrodes? k = (constant)(distance between electrodes) ?
 
  • #11
Where in the sketch is the ditch?
 
  • #12
He's going to archaeological research the castle, which
will be preceded by geophysical measurements. The challenge is also localization
said ditch. According to available information,
it is almost certain that trench was carved into the rock, its depth could be around 6 meters and width of 6-8 meters. We can assume that filling the trench extinct forms loamy - stony material with a share flushes cultural layers.For the conventional resistance measurement used four electrodes: two current (A, B) into the country "deserts" and the current I between two measuring (M, N) is then measured voltage AU, resistivity, which is the goal of our measurement is determined according to Ohm's law; in its formula is needed to add a so-called. arrangements constant k, which depends on the distance of the individual electrodes. The calculated value is then referred to as "apparent resistivity" ρz, because it describes the whole "block" hemisphere, where penetrated current:

ρz = k * AU / I

Depth of this measurement is approximately 1/3 of the distance between the electrodes A and B. How far AB hypothetically you chose if you think that the resistance measurements would allow to determine the presence of a ditch.

On the picture http://nicco35.rajce.idnes.cz/nastenka/#9.jpg I find the distance between points A and B. Please, help me
 

1. What is resistance measurement and why is it important?

Resistance measurement is the process of measuring the electrical resistance of a material or component. It is important because it helps determine the quality and functionality of electrical circuits, devices, and materials. It is also a crucial tool in detecting faults and troubleshooting electrical systems.

2. What is the purpose of using 4 electrodes for resistance measurement?

The use of 4 electrodes in resistance measurement allows for more accurate and reliable results. This is because it helps eliminate errors caused by contact resistance and electrode polarization, which can affect the accuracy of measurements when using only 2 electrodes.

3. How do you find a ditch using 4 electrodes for resistance measurement?

To find a ditch using 4 electrodes, you will need to follow these steps:

  • Drive two electrodes into the ground on opposite sides of the ditch.
  • Drive the other two electrodes into the ground on the same side of the ditch, forming a straight line with the first two electrodes.
  • Measure the resistance between the two inner electrodes.
  • If the resistance is high, it indicates that there is a ditch between the electrodes. If the resistance is low, it indicates that there is no ditch between the electrodes.

4. What factors can affect resistance measurement with 4 electrodes?

There are several factors that can affect resistance measurement with 4 electrodes, including the type and condition of the soil, the distance between the electrodes, the depth of the ditch, and the presence of other conductive materials in the area.

5. Are there any precautions to take when using 4 electrodes for resistance measurement?

Yes, there are some precautions to keep in mind when using 4 electrodes for resistance measurement. Make sure to use electrodes that are clean and free of any corrosion. Also, avoid placing the electrodes too close to each other, as this can affect the accuracy of the measurement. It is also important to follow safety protocols and use proper protective gear when working with electricity.

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