Ohm’s Law Equation can be used to calculate the relationship between voltage, current, and resistance:
Where:
V = Voltage (volts)
I = Current (amperes)
R = Resistance (ohms)
When current passes through a resistance, power is dissipated in the form of heat. Power is calculated by the following:
Where:
P = Power (watts)
These equations help provide guidance on expressing any one of the four electrical parameters in terms of any other two. A reference table of derived expressions is given below.
DC ELECTRICAL EQUATIONS | |||
VOLTAGE | CURRENT | RESISTANCE | |
POWER | |||
\[\text{I}\times\text{R}\] |
\[\frac{\text{V}}{\text{R}}\] |
\[\frac{\text{V}}{\text{I}}\] |
\[\text{V}\times\text{I}\] |
\[\frac{\text{P}}{\text{I}}\] |
\[\frac{\text{P}}{\text{V}}\] |
\[\frac{\text{V}^2}{\text{P}}\] |
\[\frac{\text{V}^2\ }{\text{R}}\] |
\[\sqrt{\left(\text{P}\times\text{R}\right)}\] |
\[\sqrt{\left(\frac{\text{P}}{\text{R}}\right)}\] |
\[\frac{\ \text{P}}{\ \text{I}^2\ }\] |
\[\text{I}^2\times\text{R}\] |
Always verify flow calculations by experiment.
*There are many parameters to consider when determining V-Factor. Click here for more information.