Ohm’s law states, “The current in a circuit is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit”. Every electrical device has information on it to help a user determine its rated power using Ohm’s law. Knowing this formula can help consumers find the right cord to meet their product’s need.
- I – Stands for Intensity or Current, which is measured in Amps. Current flows through conductors from negative to positive.
- E or V – Some tables use E for Electromotive Force or V for Volts. Volts measure the difference between two points in a circuit. It’s the push behind the current flow through a circuit.
- R – Resistance, which is measured in Ohms. The amount of resistance determines how much current will flow through. The higher the resistance, the less the current.
- P or W – Some tables use P for Power or W for Watts. This is the amount of current times the voltage level at a given point.
If you have two of the above factors, you can easily figure out the remaining two by using Ohm’s law. For instance, say you have an appliance that takes 1100 Watts and 115 Volts and you’d like to know the Amps (or Current). Simply go to the Current section in the table, find the equation that uses both Watts (P) and Volts (V) which is I = P/V. Plug in the numbers and you’ll have it figured out. In this case I = 1100/115 or I = 9.57.