Ohm's Law is the foundation of electrical engineering: V = I × R
- V (Voltage) = electrical potential difference, measured in Volts
- I (Current) = flow of charge, measured in Amperes
- R (Resistance) = opposition to current flow, measured in Ohms (Ω)
Rearranged Forms
- I = V ÷ R (find current)
- R = V ÷ I (find resistance)
Example
A 12V battery powers a 4Ω resistor. Current = 12 ÷ 4 = 3 Amps.
Power Formula
P = V × I. At 12V and 3A, power = 36 Watts.