Heteroclinic orbits in Chen circuit with time delay

Existence of Shil’nikov type of heteroclinic orbit in Chen circuit with direct time delay feedback is proved using the undetermined coefficient method. As a result, Shil’nikov criterion guarantees that the circuit has Smale horseshoes and the circuit demonstrates chaos in a rigorous analytical sense. The geometric structure of the generated chaos is determined by the heteroclinic orbits. Both the simulation and the experimental results show that chaos is indeed generated in the non-chaotic Chen circuit with the direct time delay feedback.