Realisation of Arbitrary Linear Combinations of Voltages with a Single Operational Amplifier

摘要

A method for obtaining any arbitrary linear combination of voltages using a single operational amplifier and resistances is described. The usual textbook circuit for this purpose has limitations on the weights and one normally believes that some classes of linear combinations require more than one operational amplifier for realisation. This is shown to be untrue. An example of such a case is presented.