answersLogoWhite

0

Hardly ever.

Ohm's Law is not an universal law, and is only true when the ratio of voltage to current is constant over a wide range of voltages and, then, only for that range of voltages. In other words, if the voltage to current ratio results in a straight-line graph. If the graph is curved, then the ratio of voltage to current is not constant, and Ohm's Law doesn't apply.

So Ohm's Law only applies to metal conductors, for example, providing their temperatures remain constant for changes in current -a situation that usually doesn't occur in real life. And it most certainly doesn't apply to the non-linear parts of the voltage/current characteristic curves for diodes, etc.

User Avatar

Wiki User

10y ago

What else can I help you with?