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GreenPrint
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Homework Statement
Please see the picture below.
http://img23.imageshack.us/img23/2505/capturecfk.png
The title of this section of my lab is "Voltage divider". Now I have taken this class before =(. But anyways I know that there is a whole voltage divider formula for resistors in series and parallel. I however never remembered to memorize the formula because it was much easier for me to just calculate the voltage across each resistor.
We haven't gotten to resistors in this class yet or even the formula for resistors in parallel or series and how to find their equivalent resistances. Now I'm probably sure that I'll need to this information to analyze the data which I took.
The data which I was required to take required me to do this:
1) Fill in the shape with graphite from a pencil.
2) Take one DMM, set it to measure resistance, and place the red probe at A and the black probe at B.
Now I know that a DMM applies a voltage to measure resistance, so this is the purpose of doing this.
3) Take a second DMM and set it to measure voltage place the black probe at B with the other black probe.
4) Take the red probe from the second DMM and place it at the voltage contacts (the things labeled V1', V2'... V1, V2...) and measure the data.
Analyze your results.
Homework Equations
R = [itex]\frac{ρl}{A}[/itex]
Where:
R = resistance
ρ = resistivity (in the case of graphite ρ≈1*[itex]10^{-5} Ωm[/itex]
l = length
A = cross sectional area
A = wh
Where:
w = width
h = height (thickness of the graphite layer)
V = IR
Where:
V = voltage
I = current
R = resistance
The Attempt at a Solution
Now I'm kind of confused about the data which I received. The figure is not a complete circuit (V1' contact is not connected to V2' contact etc.). I understand that a voltage source is applied between A and B. But sense it's not a complete circuit there should be no current going through to the V1' V2'... etc contacts. Yet I can measure a voltage difference between the V1' V2'... contacts and B. Why is this?
Maybe I'm over thinking this. Circuits is a lot easier when you have an actual circuit. I however seem to be confused when I have figures and not circuits without physical wires and resistors.
Thanks for any help you can provide!
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