Ohm's Law

Three of the parameters of Ohm's Law, shown as a schematic.

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. It appears on the amateur radio exams as a method of calculating electric power, usually in one of these three forms:

  1. P = E × I
  2. P = I 2 × R
  3. P = E 2 R

Try it!

Fill in any two values.

watts
volts
amperes
ohms