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Understanding The Interrelation Between Resistance And Current

Jun 09, 2019

Current generation:

How does the current come about? Current is generated because the positive and negative charges are attracted by the same and the opposite are repelled. Electrons in metal conductors actually flow from the negative to the positive. It can be imagined that there are positive charges on the top of the positive pole of the power supply, while in the metal conductor, the nucleus has little effect on the electrons, and the electrons are easy to break away from the binding of the nucleus. Thus, the electrons in the metal conductor near the positive pole of the power supply are attracted by the positive charges of the positive pole of the power supply at first. Thus, the metal conductor near the positive pole of the power supply loses electrons and becomes positive charges itself. Then the free electrons in the metal conductor are attracted by the positive charge, and the current is formed when they circulate. If the nucleus of a metal has strong attraction to the electrons, then the electrons move hard. This situation can be understood as "high resistance". If the nucleus has weak attraction to the electrons, then the electrons move easily. In fact, when the free electrons move in a direction, they collide with atoms on the lattice. According to the classical conductivity theory of metals, the frequent collision of free electrons with positive ions on the lattice will result in resistance if the movement of electrons is hindered. The frequency of collision is about 1015 times per second. In the micro world, it is not advisable to understand with simple particles. In the atomic model, the electrons outside the nucleus are distributed according to certain rules. According to the uncertainty principle, it is impossible to determine the position of electrons at the moment, only to know that the probability distribution of electrons has been in the region. The distribution of electrons is called the electronic cloud, and the state of electrons can only be known roughly by the electronic cloud. When an atom is excited by the outside world, the electrons will break away from the control of the nucleus and become free electrons. But electrons quickly release the energies and then return to the cloud. Because the number of atoms in a conductor is huge astronomical figures, and the atoms are constantly in the state of heat excitation. Statistics show that because the number of atoms in a conductor is huge, the number of free electrons is also huge, so the whole conductor looks like a sponge full of free electrons. In terms of energy relations, the electrons in the electron cloud are controlled by the nucleus, as if they are locked in a dense space; while the free electrons have relatively high energy, they can move relatively freely. The former can be called the forbidden band, while the latter is called the conduction band. Electrons transit and return between the forbidden band and the conduction band. In the micro world, it is not advisable to understand with simple particles. In the atomic model, the electrons outside the nucleus are distributed according to certain rules. According to the uncertainty principle, it is impossible to determine the position of electrons at the moment, only to know that the probability distribution of electrons has been in the region. The distribution of electrons is called the electronic cloud, and the state of electrons can only be known roughly by the electronic cloud. When an atom is excited by the outside world, the electrons will break away from the control of the nucleus and become free electrons. But electrons quickly release the energies and then return to the cloud. Because the number of atoms in a conductor is huge astronomical figures, and the atoms are constantly in the state of heat excitation. Statistics show that because the number of atoms in a conductor is huge, the number of free electrons is also huge, so the whole conductor looks like a sponge full of free electrons. In terms of energy relations, the electrons in the electron cloud are controlled by the nucleus, as if they are locked in a dense space; while the free electrons have relatively high energy, they can move relatively freely. The former can be called the forbidden band, while the latter is called the conduction band. Electrons transit and return between the forbidden band and the conduction band.