Abstract: This paper prsents a theory of three essential circuit elements (signal, network and load) for surmounting failure of Boolean algebra. First, the paper analyzes the cauese of Boolean algebra failure in digital circuits. Second, on the basis of Perfect Digital Circuits Theory, a switch operater transform theorem is proved to embody all most the overwhelming majority identical equations on switch operater which was necessary to prove one by one in literatures. After that, it is shows that the unity of digital circuits exists not only between gate level and component level circuits, but also among component level circuits structures and between dyamic and static circuits. Besides, the Karnaugh map method and algebra method are presented for designing component level circuits.