General Overview of Lecture: The course gives an insight into the theory and operation of the fundamental building blocks of digital electronics with prominence on transistor-transistor logic (TTL) and complementary metal oxide semiconductor (CMOS) integrated circuit logic families. In order to further understand vividly, the theory behind the course its introduces distinct different between analog and digital system, digital circuits and system, number system and codes, Boolean algebra the basic mathematical tool required to synthesize and analyze a vital class of switching circuits. Simplification of logic expressions using K-maps, the understanding of combinational logic circuits design analysis and synthesis, derivation of algorithms for minimal SOP and POS forms from K-maps. The study of logical properties of flip-flops, which serve as memory devices in sequential switching circuits, the design of counters, adders, subtractors, sequence detectors and related circuits. Implementation of logic functions using decoders, encoder circuits structures. Multiplexers/data selector, circuit structures, Application of multiplexers and demultiplexers/data distributors. On to design comparators arithmetic overflow detection. Design example of a computer arithmetic logic unit and computer aided design of modular systems.