Ohm's Law:

In the year of 1827, George Simon Ohm discovered that there was a definite relationship among current, voltage, and resistance in an electrical circuit.  Ohm's Law describes this relationship and could be begins within three ways.

1. Applied voltage equals circuit current times the circuit resistance. In Equation (1-2) it represent mathematical concept.

E = I x R         or        E = IR                         (1-2)

2. Current is equal to the applied voltage divided by the circuit resistance.  Equation (1-3) is a mathematical representation of this concept.

I = E/R                                   (1-3)

3. Resistance of a circuit is equal to the applied voltage divided by the circuit current. Equation (1-4) is a representation of this mathematical concept.

R (or ?) = E / I                     (1-4)

where

I = current (A)

E = voltage (V)

R = resistance (?)

The third can be calculated if any two of the component values are known.