Ohm's Law

Ohm's Law

Ohm's law give de relations between Voltage, Resistance and Current in pure resistive circuit through two points.

Voltage and currente cannot be observed directly are often difficult to understand. To clarify these terms, some people make Electronic-hydraulic analogy sometimes called drain-pipe theory, the comparison between electrical circuits and water flowing in pipes. Here is a chart of the three electrical units (volt, Ampere, Ohm).

Electrical QuantityDescriptionUnitWater Analogy
Resistance Measure how difficult it is for current flow in a circuit Ohm
Measure how diffilcult it is for water flow through a pipe
Current Measure the flow of charge in a circuit. Ampere
Amount of water flowing
Voltage or
Potential Difference
Measure of the Energy difference per unit charge between two points in a circuit. Volt (V) Water Pressure 

I=V/R ohm's Law


  • I : Current, Ampere ( A )
  • R : Resistance, Ohm ( Ω )
  • V : Voltage, Volt ( V )


V=50 Volts
I=2 Amps

Ohm's Law Calculator

Volts (V)Amps (I)Ohms (R)Watts (P)

Ohm's Law Simulation