# Resistance (Electrical)

Written by Jerry Ratzlaff on . Posted in Electrical

Resistance is the ability to resist or prevent the flow of current. In order to overcome the resistance and get the current to flow a higher voltage will be required. Resistance is measured in Ohms, represented by $$R$$ and has a symbols $$\Omega$$.

Ohm is a unit of resistance. A constant current of one ampere produces a force of one volt.

## FORMULA

$$Ohms = \frac{Volts}{Amps}\;\; = \;\;R = \frac{V}{I}$$

$$Ohms = \frac{Volts^2}{Watts}\;\; = \;\;R = \frac{V^2}{P}$$

$$Ohms = \frac{Watts}{Amps^2}\;\; = \;\;R = \frac{P}{I^2}$$

## TYPICAL COPPER WIRE RESISTANCE

For stranded copper conductors at 60°F