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'''Ohm's law''' is a mathematical relationship of three variables in an electronic [[circuit]] containing a resistive element. It states that the voltage across a resistive element is equal to the [[current]] passing through the resistive element times the [[resistance]] of the resistive element.
'''Ohm's law''' is a mathematical relationship of three variables in an electronic [[circuit]] containing a resistive element. It states that the voltage across a resistive element is equal to the [[current]] passing through the resistive element times the [[resistance]] of the resistive element.
In mathematical terms, this is written as:
In mathematical terms, this is written as:
:I: Current through resistive element
:I: Current through resistive element
:R: Resistance of resistive element
:R: Resistance of resistive element
In this equation, R is always constant, regardless of the current and voltage. In real life, however, the temperature of a resistor will rise as the current through it increases. Since resistance and temperature are positively correlated, Ohm's law becomes only an approximation (and sometimes a very bad approximation) when the resistive element heats up. For example, an incandescent light bulb does not follow Ohm's law because it becomes hot very rapidly when a current is applied.
[[Category:Mathematics]]
[[Category:Mathematics]]
[[Category:Physics]]
[[Category:Physics]]
[[Category:Electrical Engineering]]
[[Category:Electrical Engineering]]