Calculate voltage, current, resistance, and power using Ohm's law.
Ohm's Law states that voltage equals current times resistance (V = IR). It's the fundamental relationship in electrical circuits.
Divide voltage by current: R = V/I. For example, 12V ÷ 2A = 6Ω.
Power (watts) is the rate of energy transfer. P = V × I. Higher power means more energy consumed per second.