This guide shows you the proper formula to use to calculate with Ohm’s Law.
A. When Volts and OHMS are known:
| Amperes = | VoltsOHMS | or, I = | ER |
Example: Find the current of a 120 volt circuit with a resistance of 60 OHMS.
| I = | ER | = | 12060 | = 2 Amperes |
B. When Watts and Volts are known:
| Amperes = | WattsVolts | or, I = | PE |
Example:A 120 Volt Circuit has a 1440 Watt Load. Determine the current.
| I = | PE | = | 1440120 | = 12 Amperes |
C. When OHMS and Watts are known:
Example: A circuit consumes 625 watts through a 12.75 OHM resistor. Determine the current.
* One Electrical Horsepower = 746 watts. Electric Motors are rated in horsepower.
** One kilowatt = 1000 watts. Generators are rated in kilowatts.
