Ohm's Law Calculator

Ohm's Law states V = IR: Voltage (V) equals Current (I) times Resistance (R). It's fundamental for analyzing electrical circuits. If you know any two values, you can calculate the third. Named after Georg Ohm who discovered this relationship in 1827.

Voltage is electrical potential difference, measured in Volts (V). Think of it as electrical pressure - it pushes electrons through a circuit. A 9V battery provides 9 Volts of electrical pressure. Higher voltage can push more current through the same resistance.

Current is the flow rate of electrical charge, measured in Amperes or Amps (A). 1 Ampere means 1 Coulomb of charge flowing per second. It's like water flow in a pipe - more current means more electrons flowing past a point.

Resistance opposes current flow, measured in Ohms (Ω). Materials like copper have low resistance (good conductors), while rubber has high resistance (insulators). Higher resistance reduces current for the same voltage, converting electrical energy to heat.

Ohm's Law applies to ohmic materials where resistance is constant (most metals, resistors). It doesn't apply to non-ohmic devices like diodes, transistors, or light bulbs where resistance varies with current or voltage.

To find voltage: V = I × R. To find current: I = V / R. To find resistance: R = V / I. Example: A 12V battery through a 4Ω resistor produces I = 12/4 = 3A current.