Ohm's law, discovered by German physicist Georg Simon Ohm in 1827, states that the current through a conductor is directly proportional to the voltage applied, provided the physical conditions of the conductor remain unchanged. It explains the relationship between voltage, current, and resistance, and is used by electricians, automotive technicians, and stereo installers. The law is represented by the equation V=I*R, where V is voltage, I is current, and R is resistance.