Digital Logic

Contributors: SFUptownMaker
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Digital, or boolean, logic is the fundamental concept underpinning all modern computer systems. Put simply, it’s the system of rules that allow us to make extremely complicated decisions based on relatively simple “yes/no” questions.

In this tutorial you will learn about…

Digital circuitry

Digital logic circuits can be broken down into two subcategories- combinational and sequential. Combinational logic changes “instantly”- the output of the circuit responds as soon as the input changes (with some delay, of course, since the propagation of the signal through the circuit elements takes a little time). Sequential circuits have a clock signal, and changes propagate through stages of the circuit on edges of the clock.

Typically, a sequential circuit will be built up of blocks of combinational logic separated by memory elements that are activated by a clock signal.


Digital logic is important in programming, as well. Understanding digital logic makes complex decision making possible in programs.

There are also some subtleties in programming that are important to understand; we’ll get into that once we’ve covered the basics.

Suggested Reading

Before getting started, it might be a good idea to review our tutorial on binary numbers, if you haven’t already. There is a small amount of discussion on boolean logic in there, but we’ll be going much further into the topic here.Here are some other topics you should be familiar with before getting started.