Physics Laws & Theorems
Basic

Ohm's Law

Voltage across a resistor equals current times resistance.

Formula

V=IRV = IR

Variables

VVoltage
ICurrent
RResistance

Example

A 9 V battery across a 3 Ω resistor drives 3 A of current.

Did You Know?

Ohm's law is the single most-used relationship in all of electronics.

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