In circuit analysis, the dot convention is a convention used to denote the voltage polarity of the mutual inductance of two components. Two good ways to think about this convention:
Voltages might be a less confusing way of looking at this concept, but might be harder to remember. As shown below, the dot convention distinguishes between two cases, where the polarities of the top node are the same, and when they are different. There are two ways to write each case, and the equivalent ways of writing them are shown.
