This paper presents an approach for electronic circuits modelling based on index matrices. The last one is developed by the authors as more general tool, but it is applied mostly for electrical circuits representation as well as for evaluation of voltage and amperage in time. Basic electronic components and their junction are modelled in a simple manner. The presented index matrices on a PID controller shows that this approach can be performed for more complex components. The proposed graphic user interface handles various parameters and visualizes time dependences of voltage and amperage values.