Ohm's law

In the same circuit, the current in the conductor is proportional to the voltage across the conductor and inversely proportional to the resistance of the conductor. This is Ohm's law.

The derivation of the law of Ohm's law I=U/R, R=U/I or U=IR, cannot say that the resistance of a conductor is proportional to the voltage across it and inversely proportional to the current passing through it, because the resistance of the conductor is a kind of its own Attributes, depending on the length of the conductor, the cross-sectional area, the material and temperature, and the humidity (the second stage does not involve humidity), even if there is no voltage across it, no current is passed, and its resistance is also a fixed value. (This setting can be regarded as constant under normal circumstances, because the resistance value is uncertain for the photoresistor and the thermistor. For some conductors, superconductivity exists at very low temperatures. The phenomenon, these will affect the resistance of the resistor, and have to be considered.)

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