The Chua circuit is the simplest electronic circuit which exhibits chaos, and few bifurcation phenomena as well, as verified from numerous laboratory experiments, computer simulations, and also rigorous mathematical analysis. The behaviour of Chua’s circuit system has been studied in thousands of studies and articles, and it is still surprising to find that it can generate a lot of topologically distinct attractors. Although this system is totally different and was obtained in another way, its chaotic behaviour reminds us of the Lorenz system. For these reasons, the topic of studying the stability of the Chua system remains actual and important both from the mathematical (theoretical) and engineering (practical) standpoint. The present paper aims to analyse the Chua modified model. Namely, the cubic modified model is taken into account. Reformulating this model as a second order differential system, its approach from analytical and computational standpoint becomes gives very interesting results. The phase-portrait of the model is taken into account, for convenient parameter values according to recent literature analysis. The simulations obtained are further correlated to the analytical approach.