why electric current always flows frm postive to negative
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higher concentration to lower concentration
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Ok, there are a lot of answers here, most generally right in one way or another, with small errors in them. This is what I know:
The first thing to answer is what current is; it is the flow of electrons, not protons, not neutrons, not anything else.
Electrons in an atom have valences or orbits; some are tightly bound and some are more distant and loosely bound.
Electrons always have a negative charge which is always attracted to a positive charge. When there is enough of a positive charge outside of the atom, to overcome their attraction to the protons in the nucleus, they can leave the atom. If there is enough potential they can be emitted as a high energy photon or free electron; however, at lower energy levels they simply jump to another atom’s valence. This is how semiconductors work.
When an electron leaves an atom, it creates a vacancy or hole in the atom’s valences. This hole is a free space which another electron can jump into. As one electron leaves, another one may jump in. As the electrons always move towards the positive attractor, the holes will tend to flow to the negative. You end up with two descriptions of current, one for electron flow and one for hole flow.
Hole flow is usually called conventional current, and flows from positive to negative. Electron flow goes in the reverse direction, from negative to positive voltages. It is easy to remember by the fact that electrons flow towards the positive.
For most practical purposes, it is more productive and less confusing to disregard the current direction and simply concentrate on the voltage as being a polarized potential and the current as being a continuous flow.
The first thing to answer is what current is; it is the flow of electrons, not protons, not neutrons, not anything else.
Electrons in an atom have valences or orbits; some are tightly bound and some are more distant and loosely bound.
Electrons always have a negative charge which is always attracted to a positive charge. When there is enough of a positive charge outside of the atom, to overcome their attraction to the protons in the nucleus, they can leave the atom. If there is enough potential they can be emitted as a high energy photon or free electron; however, at lower energy levels they simply jump to another atom’s valence. This is how semiconductors work.
When an electron leaves an atom, it creates a vacancy or hole in the atom’s valences. This hole is a free space which another electron can jump into. As one electron leaves, another one may jump in. As the electrons always move towards the positive attractor, the holes will tend to flow to the negative. You end up with two descriptions of current, one for electron flow and one for hole flow.
Hole flow is usually called conventional current, and flows from positive to negative. Electron flow goes in the reverse direction, from negative to positive voltages. It is easy to remember by the fact that electrons flow towards the positive.
For most practical purposes, it is more productive and less confusing to disregard the current direction and simply concentrate on the voltage as being a polarized potential and the current as being a continuous flow.
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