This is the complete course on digital circuit design for students pursuing B.E/B.Tech degrees in Electronics and Communication engineering, Electrical and Electronics engineering, Computer Science and Engineering, and Information Technology departments. The topics covered in this course are 1. Number systems (decimal, binary, octal, hexadecimal) and their conversions, 2. Boolean algebra (boolean simplification and De Morgans laws), 3. Karnaugh Maps for simplification of boolean expressions, 4. Logic gates and truth tables, 5. NAND NOR logic gates and logic function realization, 6. Combinational circuit design, 7. Encoders, Decoders, Multiplexers, and Demultiplexers, 8. Latches and Flip Flops (RS latch and flip flop, D latch and flip flop, JK latch and flip flop, T latch and flip flop), 9. Sequential circuit design, 10. Shift Registers and design of counters, 11. Memory elements (RAM, ROM), 12. Realization using PLA, and PAL, and 13. Design of finite state machines. The topics can be tailored to the syllabus of various universities and departments. I will explain each concept in detail and then will illustrate the various design procedures. Knowledge of digital circuits is essential in taking up simulation courses using VHDL and Verilog HDL. This course will also be useful for taking up various competitive examinations.