Output depends only on current inputs, such as adders and multiplexers.
Combinational logic has no memory: outputs depend only on current inputs. Design: specify truth table, simplify, implement. Examples: adders, comparators, encoders, decoders, ALUs. Concerns: propagation delay and glitches (hazards).
A BCD to seven-segment decoder.
Combinational logic produces outputs from current inputs only, and it is the logic used for arithmetic, selection and decoding.
Output depends only on current inputs, such as adders and multiplexers.
Combinational logic produces outputs from current inputs only, and it is the logic used for arithmetic, selection and decoding.
Combinational outputs depend only on present inputs, while sequential logic depends on stored state and therefore on history.
Different paths have different delays, so outputs can change briefly before settling, which matters when the output drives a clock or a reset.
Typical applications include building a comparator to check whether two bytes match, designing an address decoder for a memory chip and creating a priority encoder for interrupt requests.
Study "Karnaugh maps" first (topic 39 of 104 in Electronics & Embedded). It covers the groundwork this topic builds on.
Critical path. Static hazards. Fan-out limits.
A BCD to seven-segment decoder.
The next topic is "Adders and subtractors", which builds directly on this one.
It is classed as Intermediate in Electronics & Embedded (topic 40 of 104). It is an intermediate topic. Work through the beginner topics in Electronics & Embedded first.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.