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I want to confirm if I understand something correctly.

We call the "high potential terminal" the positive side (cathode).

Though, electrons move from negative to positive. Logically, electrons' potential energy is decreasing so the high potential terminal should be the negative side.

In my opinion, from the electrons' perspective, the high potential terminal is the negative side, but since the current flows in the opposite direction, we always talk from the current's perspective, hence why we call the high potential terminal the positive side. Is this the correct logic?

Duke William
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Giorgi
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1 Answers1

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You are confusing “potential” with “potential energy”. The potential is the potential energy per unit positive charge. So the side where a negative charge carrier has a low potential energy is by definition the high potential side.

You state “from electron's perspective, high potential must be negative side”. This is incorrect. Even from an electron’s perspective it still has a negative charge. So (assuming the negative terminal is grounded) at the positive terminal an electron has negative potential energy, and when you divide the negative potential energy by the negative charge the positive side is the high potential side. Even from the electron’s perspective.

By the way, in circuit theory there is no benefit in thinking about electrons. Electrons are useful in chemistry and in quantum electrodynamics. They are unnecessary in circuits and in classical electromagnetism.

Dale
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