Ohm’s Law is a basic law of physics which states that current passing through a conductor is proportional to the input voltage.

Mathematical Equation

V ∝ I

Where ‘V’ is voltage and ‘I’ is current and ‘R’ is constant of proportionality.

R is actually resistance of conductor which is assumed constant.

Removing this proportionality we get:

V = IR

We can use this formula to find current and resistance as well:

I = V/R

and R = V/I


The Ohm’s Triangle

You can easily memorize the above equations from the triangle.

  1. Draw a triangle.
  2. Divide it into 3 parts
  3. Mention V on top side
  4. Mention I on bottom left side
  5. Mention R on bottom right side.
  6. To find V place your thumb on V and observe I and R. Here we get equation IR or better I.R
  7. To find I place your thumb on I and observe V and R. Here V is in numerator and R is in denominator we get equation I = V/R
  8. Finally, place your thumb on R and observe V and I. We get R = V/R