How do you determine a dipole?

Any separation of charge is a dipole. A permanent dipole results from an unequal distribution of charge eg. in a covalent bond. A covalent bond between two of the same atoms is not a permanent dipole. But a covalent bond between two different atoms is a permanent dipole. However, if the difference in electronegativity is < 0.5, the dipole can be said to be insignificant. This means that C-H bonds are non-polar. This is convenient in explaining why hydrocarbons do not dissolve in water. It should be noted that a molecule can have many dipoles operating in different directions but no overall dipole or an insignificant overall dipole.