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Electric current (Electric charge (Unit (Coulomb (C)), Matter is made up…
Electric current
Electric charge
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Matter is made up of atoms which have positively charged nuclei and negatively charged electrons surrounding them. Charge is quantized as a multiple of the electron or proton charge.
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The influence of charges is characterized in terms of the forces between them (Coulomb's law) and the electric field and voltage produced by them.
Protons and electrons have the same magnitude and size of charge, but are opposite in polarity. The implication of that is that the proton and electron will strongly attract each other, because "like charges repel and unlike charges attract".
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One of the fundamental symmetries of nature is the conservation of electric charge. No known physical process produces a net change in electric charge.
Ohm's law
The drift velocity of charges through the material is proportional to the electric field in the conductor.
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The electric current that flows through the conductor is directly proportional to the voltage applied to it.
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Circuit elements
Made up of localized circuit elements connected by wires which have essentially negligible resistance.
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Voltage law
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Since voltage is electric potential energy per unit charge, the voltage law can be seen to be a consequence of conservation of energy.
Current Law
The electric current in amperes that flows into any junction in an electric circuit is equal to the current which flows out.
This can be seen to be just a statement of conservation of charge. Since you do not lose any charge during the flow process around the circuit, the total current in any cross-section of the circuit is the same.
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Kirchhoff's laws
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2nd law or the Loop Rule
Around any closed loop in a circuit, the sum of the potential differences across all elements is zero. This law is a statement of energy conservation, in that any charge that starts and ends up at the same point with the same velocity must have gained as much energy as it lost.
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Units
Measured in Coulombs/second, which is named Amperes. The standard abbreviations for the units are 1 A = 1C/s.
Circuits
Elements
Source of the power
For the direct current circuits, this is a battery.
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In most DC electric circuits, it can be assumed that the resistance to current flow is a constant so that the current in the circuit is related to voltage and resistance by Ohm's law.
