Ohm's law states that the
current through a
conductor between two points is directly
proportional to the
voltage across the two points. Introducing the constant of proportionality, the
resistance, one arrives at the usual mathematical equation that describes this relationship:
where is the current through the conductor in units of
amperes,
V is the voltage measured
across the conductor in units of
volts, and
R is the
resistance of the conductor in units of
ohms. More specifically, Ohm's law states that the
R in this relation is constant, independent of the current.