Control systems are essential to today's complicated electronics. They are used throughout the feedback systems in order to tune output to target. Gellerally, the optimization of a control system has mostly performed by focusing the stabilization of the output itself. Therefore, the magnitude of improvement in many cases was limited with a poor reproducibility. In this study, the feedback control loop was shut off, the output of the whole circuit was considered as the signal and a dynamic characteristic was used to evaluate the functionality. The results showed a significant improvement. The approach can be applied for all control system improvement and will probably trigger the quality engineering applications in electrical fields.