Digital electronics represents information with defined logic ranges and implements Boolean, arithmetic, storage and control functions. The sections below move from number systems and logic operations to gates, families, combinational circuits, sequential circuits, registers, counters, encoders, decoders, adders, subtractors and memory.
Combinational output depends on present input. Sequential logic also stores state, usually in latches or flip-flops. Reliable hardware needs valid logic levels, adequate noise margin and complete timing analysis. In clocked circuits, check propagation and contamination delays, clock period, clock skew, setup time and hold time. Invalid or asynchronous inputs may need synchronisation because violating timing constraints can produce metastability or corrupt state.
