In this paper mainly three applications are controlled by PLC (Programmable logic controller).which are DC Motor, Stepper Motor, Traffic Light control applications. The hardware components interact with each other and study to how control with the help of PLC. In DC motor application, foreword and reversal control of motor using PLC. In application of Stepper motor, control the speed and direction of rotation with the phase angle. In Traffic light. The system operates with traffic lights implemented with LED technology. The proposed system makes use of the transmission media to communicate different traffic light groups with a central regulator in order to exchange information about the lighting elements. From the regulator, the status and operation of the traffic light group can be monitored and changed according to traffic conditions and time. This is reduction of maintenance cost and accurately control the traffic light system.