Understanding Voltage Reference Points and Potential Differences | Explained

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The discussion clarifies the concept of voltage reference points and potential differences. It establishes that 5 volts referenced to ground is indeed 5 volts, while 5 volts referenced to 2 volts results in a potential difference of 3 volts, not 7 volts. The analogy of apples illustrates that subtracting a reference point does not increase the total but rather defines the difference. The key takeaway is that potential difference is calculated as the voltage at one point minus the voltage at another, emphasizing the importance of consistent reference points. Understanding these principles is crucial for accurate electrical measurements and applications.
e44-72
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Hello

I know that 5 volts in reference to ground (0 volts) is 5 volts as there is a potential differencce of 5 volts between 0 and 5 volts.

Does this mean 5 volts in reference to 2 volts would be 7 volts as there is a potential difference of 5 volts between 2 and 7 volts?

Thank you for any replies
 
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What are "5 volts in reference to 2 volts"?
If you connect the "-"-side of a 5 volt power supply to a cable which has +2V (with your definition), the "+"-side will have +7V.
 
e44-72 said:
Hello

I know that 5 volts in reference to ground (0 volts) is 5 volts as there is a potential differencce of 5 volts between 0 and 5 volts.

Does this mean 5 volts in reference to 2 volts would be 7 volts as there is a potential difference of 5 volts between 2 and 7 volts?

Thank you for any replies

If you are talking apples to apples (same ground reference in the same circuit) then 5 volts is 3 volts above 2 volts.

Your argument is exactly like saying that if I have 5 apples and you take away 2 of them, I should now have 7 because there is a difference of 5 between 2 and 7.
 
Voltage difference = Voltage on point A - Voltage on point B

Examples

Va Vb Difference
5 0 5
5 2 3
5 -2 7
-5 -3 -2
 
potential diff is exactly that, -5 to -10

potential being the power-of-the-universe/desire to go from one difference (ie ground state) to another

difference.. being the "key word" in "potential difference" : excludes the ground/zero state

(as the ability of voltage/potential difference to perform is the same)
 
It may be shown from the equations of electromagnetism, by James Clerk Maxwell in the 1860’s, that the speed of light in the vacuum of free space is related to electric permittivity (ϵ) and magnetic permeability (μ) by the equation: c=1/√( μ ϵ ) . This value is a constant for the vacuum of free space and is independent of the motion of the observer. It was this fact, in part, that led Albert Einstein to Special Relativity.

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