This paper proposes a new method of finding the Thevenin equivalent circuits for the transformer and partial–ideal operational amplifier systems that have not been systematically solved by traditional approaches now. This paper also exploits some strong improvements to solve the complicated dependent source circuit and mutual coupling circuit. Five comparative examples are demonstrated to show the significant merits that our method owns over the traditional approaches including the open-circuit voltage and short-circuit current method, matrix node voltage (mesh current) method, modified nodal (mesh) analysis, reference node r model, reflected impedance method, and virtual ground method. [ABSTRACT FROM AUTHOR]