Design is relatively simple control circuit has a large advantage when

This shows that concrete and effective circuit design students and trainees learning in the larger problems. In the relay control circuit design, many designers are using empirical design method. This method is relatively simple in the design of the control lines that greater advantages, but in the design of more complex control  electric transformer the show some limitations. First, the high requirements for designers, designers need to be familiar variety of typical industrial systems control lines and rich practical experience and design skills accumulation; Second, the design of low power transformers , in engineering applications is inconvenient, requiring designers in the design process should be repeated to revise and improve, through continuous testing demonstrated to meet the requirements of production process, spend a lot of time and effort;