Digital Electronics

This is a complete, web-native course in Digital Electronics for second- and third-year undergraduates in electrical and electronics engineering. Its thirty chapters run from the number systems a digital machine uses to represent a quantity before any logic acts on it, through to a VHDL description that a synthesiser turns back into gates. Each chapter lives on its own page — readable on any device, linkable, searchable and free to share.

Nothing on these pages is decorative or borrowed. Every figure is drawn inline as SVG in the page itself — every gate-level schematic, K-map grid, timing diagram, state diagram and converter waveform — so it scales to any screen, prints cleanly, carries a written description for a reader who cannot see it, and cannot go missing the way an image file can. Every numerical result is computed rather than quoted: each base conversion, noise margin, propagation delay, counter modulus and quantisation step was evaluated before it was written down, and every minimised Boolean expression was checked against the original function by exhaustive truth table.

The six parts follow the order in which the subject has to be learnt. Parts 1 and 2 are the algebraic foundation: how a quantity is coded, and how a required behaviour is written as a Boolean statement and then reduced to the fewest gates that still implement it. Part 3 is the electrical reality behind the symbol — what a real TTL or CMOS gate can drive, how fast it switches, how much noise it tolerates, and what has to happen where two families meet. Parts 4 and 5 are the circuits: first the standard combinational blocks every datapath is assembled from, then the latches, flip-flops, counters, registers and state machines that give a circuit a memory of where it has been. Part 6 is the devices — semiconductor memories, programmable logic from the PLA to the FPGA, the converters that meet the analogue world, and the hardware description language that ties the whole subject together.