# Ohms Law and Other Formulas

#### What is Ohms Law?

Ohms Law is the relationship between Voltage (V), Resistance (R), and Amperage (I).

Using Ohms Law and the equations in the wheel you can calculate Voltage, Resistance, Amperage, and Power(Watts). All you need are any two values in the formula.

$V= I x R$

$R=\frac V I$

$ I=\frac V R $

#### What is Voltage Drop?

Voltage Drop is the calculation of how the resistance in a wire and the current moving through resistance reduces the voltage used to induce the current. The base formula is $V= I x R$.

The formula below takes into account both conductors used in the circuit and you only need to know the resistance per thousand feet of the wire gauge in use.

*V*_{drop}_{ (V)}= *I*_{wire}_{ (A)} × (2 × *L*_{(ft)} × *R*_{wire}_{(Ω/kft)} / 1000_{(ft/kft)})

*V* is the voltage drop measured at the end of the wire run.

*I* is the total current or load of the devices on the circuit measured at the end of the wire run.

*L* is the one-way length of the wire run from the power source to the end of the wire run.

*R* is the resistance of 1000' feet of the wire gauge in the wire run.