1. IR drop is a potential drop due to solution resistance. It is the difference in potential required to move ions through the solution. IR drop results from the electric current flow in ionic electrolytes like dilute acids, saltwater, etc. 2. Kirchhoff’s Current Law states that the current going into a node or junction must be the same as the current leaving the node or junction. 3. Kirchhoff’s Voltage Law states the sum of the voltage drops in a circuit must equal the applied or source voltage.