Robin Barton  
 
 Basic Electrical CalculationsThere are two key calculation triangles for basic electrical circuits. The first gives the relationship between voltage (V), current (I) and resistance. The second gives the relationship between power (W), voltage (V) and current (I). These calculations are for Ohmic conductors only.
So if any two of the variables are known, the third can be calculated: I know: I & R V & I V & R V = A × Ω
So if any two of the variables are known, the third can be calculated: I know: V & I W & V W & I W = V × A These can be combined giving us:
 
