Increase in voltage VS kinetic energy I understand that voltage is the potential (J/C) difference between 2 points. I also understand that as potential energy is lost, kinetic energy is gained. I am trying to do one of the classic "electron moved to a location with higher voltage, what is it's speed?" problems, but it's not making sense to me.
If the voltage goes up as the electron moves, that means the electron has gained PE, doesn't it? (Because the difference in potential is greater now [and difference is final minus initial].) So...that means it is going slower.
But that doesn't seem to actually be true. Somehow, I've gotten this completely backwards!
EDIT:
For example, I have this HW problem: "An electron accelerates from rest from one capacitor plate to another 5.0 kV higher in potential. With what speed does it hit the other plate?" And in the answer sheet, we take the 5 kV and multiply it by the electron's charge to find the PE energy lost in joules, and then use that information to find KE. But according to my thinking above, this would be what the electron gained in PE--and lost in KE! Not vice versa!
 A: Aha, I believe I see the confusion now. You are confusing the potential energy of a circuit with the potential energy of an electron. Let me explain...
Potential energy is just the tendency of something to move. An object will want to move towards a spot of lower potential.


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*Like a book on a shelf; it wants to fall down, since the potential energy is lower there.

*Same for an electron. If you put an electron close to the negative end of a battery, it will repel because the further away it gets, the smaller is the potential energy.

*But a positive charge would be attracted and would move closer to the negative battery end! The potential energy is in this case smaller the closer they are.


The point is that potential energies depend on the type of "object". In the case of electronics, it depends on the sign of the charge. 

In general when we talk about potential energies or potentials or voltages of some circuit, we don't necessarily know what the moving charges are. In other words, we don't know what the charge carriers are.


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*They can be negative such as electrons in usual metallic wires.

*They can be positive such as holes in semiconductors. A hole is a missing electron and corresponds to a positively charged carrier. 

*They can be a mix such as ions in a conducting solution (an electrolyte). When there is a voltage over some electrodes stuck into this solution, negative ions move to the positive one and positive ions to the negative one.


Current flowing is the total motion of moving (or drifting) charge. As you see there are several types of current; which just means several types of charge carriers.
If we talked about potential of a specific type of charge, we would have to know which carrier is present. To avoid having to know this, people in the physics world have decided that whenever we talk about potential, we talk about it as if the charge carriers are positive. (The same goes for direction of current, direction of electric field etc.)
With this consensus, it is easy to just flip it around, if we know that we have negative charge carriers in a specific case. If I tell you that the current flows clockwise, but you know that it is metal wires so electrons are the carriers, then you know that the electrons are moving counterclockwise.
And the same applies for the potential: If I tell you that there is high potential at point A and lower potential at point B, then I mean that a positive charge sees it this way. A positive charge would want to move towards point B rather than A. But an electron would feel the exact opposite - whatever repels the positive charge from point A, attracts a negative charge. And vice versa. An electron would see a lower potential at point A and a higher at point B.
I hope I understood the point in your question and have addressed it in this answer. Otherwise please let me know.
