Timeline for What is the sign of voltage if I move from the positive part to the negative part?
Current License: CC BY-SA 4.0
19 events
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| Dec 1, 2019 at 21:54 | vote | accept | Álvaro Franz | ||
| Dec 1, 2019 at 21:29 | answer | added | The Photon | timeline score: 3 | |
| Dec 1, 2019 at 20:13 | comment | added | The Photon | Your animated gif is showing a passive device which is absorbing electrical power (shown by the power arrows going away from the circuit) if the device were a power source, delivering electrical power, the relative signs of voltage and current would be opposite (one would be reversed, not both). Also they're showing conventional current, as indicated by the + signs indicating charge. | |
| Dec 1, 2019 at 19:48 | history | edited | Álvaro Franz | CC BY-SA 4.0 |
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| Dec 1, 2019 at 19:41 | comment | added | Álvaro Franz | @ThePhoton "The 3 V source is marked with a "+" on the terminal connected to node e. So we know node e is 3 V higher than node b.". I had the idea that the $+$ means that that area is just positive charge. If it means higher potential, would the movement not be backwards (since equilibrium is always reached at less potential)? I updated the question with an image that represents exactly what I mean. I am not critizising you, I really appreciate the help. I am just saying I still do not grab the idea. It's like: "Hey don't worry, direction does not matter." But of course it does, in my opinion. | |
| Dec 1, 2019 at 19:28 | history | edited | Álvaro Franz | CC BY-SA 4.0 |
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| Dec 1, 2019 at 3:18 | history | edited | Qmechanic♦ | CC BY-SA 4.0 |
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| Dec 1, 2019 at 2:37 | comment | added | The Photon | The 3 V source is marked with a "+" on the terminal connected to node e. So we know node e is 3 V higher than node b. You don't have to think at all about whether the charge carriers are electrons or positrons to read that from the diagram. In the US the convention is $V_{eb} = V_e-V_b$, so we'd say $V_{eb}=+3\ {\rm V}$. I don't 100% know what the convention is in your country but the fact that the answer is supposed to be what you say it's supposed to be tells me it's most likely the same as here except for using $U$ instead of $V$. | |
| Dec 1, 2019 at 2:25 | answer | added | rob♦ | timeline score: 1 | |
| Dec 1, 2019 at 1:59 | comment | added | Álvaro Franz | @G.Smith I have the idea that voltage is never a property of a point. It is a measure between two points. By "from x to y" I mean measuring x as the start and y as the end. If I say a positive voltage from a to b, to me that means that the electric current will go from a to b due to the voltage from a to b. But if I have a negative voltage from a to b, it means to me that the electric current will go backwards from b to a. Of course, I don't know if that is true. And I think that is where my confusion lies. | |
| Dec 1, 2019 at 1:51 | comment | added | Álvaro Franz | @ThePhoton I describe the effect of the voltage source connected between e and b as e being positively charged and b being negatively charged. In this case the positive charges cannot move because they are not free to do so, but the negative charges can be transported thanks to electrons. So, electrons will want to go from b to e. So the voltage to me is positive from b to e and negative from e to b. | |
| Dec 1, 2019 at 1:07 | comment | added | G. Smith | Take your pick and be consistent, or use the definition in your book for $V_{ab}$. | |
| Dec 1, 2019 at 0:57 | comment | added | G. Smith | What does “tension from $a$ to $b$” mean? The voltage “between” $a$ and $b$ can be defined as the potential at $a$ minus the potential at $b$ or vice versa. | |
| Dec 1, 2019 at 0:20 | comment | added | The Photon | And how do you describe the effect of the voltage source connected between those nodes? | |
| Nov 30, 2019 at 23:55 | history | edited | Álvaro Franz | CC BY-SA 4.0 |
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| Nov 30, 2019 at 23:41 | comment | added | Álvaro Franz | @ThePhoton I would say it is $-3 V$ because it goes from + to -, and electrons want to carry the charge from - to + | |
| Nov 30, 2019 at 23:06 | comment | added | The Photon | Would you say $U_{eb}$ is -3 V or +3 V? | |
| Nov 30, 2019 at 22:24 | history | edited | Álvaro Franz | CC BY-SA 4.0 |
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| Nov 30, 2019 at 22:19 | history | asked | Álvaro Franz | CC BY-SA 4.0 |