Impedance Combiner is a free Android application developed by N. G. Tech that calculates the total driving point impedance of an electrical circuit. It accepts complex numbers as input, which can be total resistive, reactive, or a combination of both. The app is designed to be used by engineers and electricians who need to calculate the total impedance of a circuit quickly and accurately.

The app's expression accepts two operators: "+" and "", where the former is used to combine series impedances, and the latter is used to combine parallel impedances. The operator has a higher precedence than the "+" operator, and brackets can be used to establish precedence. The app also has a help section with several examples to help users understand how to use it.

Overall, Impedance Combiner is a useful tool for engineers and electricians who need to calculate the total impedance of a circuit. Its simple yet powerful expression and easy-to-use interface make it a must-have app for anyone in the field.