One of the algorithms extensively used in diagnosis of electronic circuits and systems is the artificial neural networks (ANNs)Artificial Neural Networks (ANN). These were proven on many occasions as a powerful tool to recognizing (separate) among the faulty responses of the system obtained by simulation the one which is the most similar to the measured. In this chapter, the very basics of analog feed-forward ANNs will be given with the goal to help the reader to start implementing the concept by her/him using already available open-source software solutions.