Talk:Digital Circuits/Logic Operations

I wrote up a template for drawing up a basic truth-table for a 2 input, 1 output logic gate. if you use the template, it will draw a truth table as such:

i figured making an automatic template would help to alleviate some of the pain of constantly drawing up a truth table every time you want one. Also, feel free to edit the above template at Template:Digital Circuits Truth Table if you want to make it prettier, easier to read, etc... --Whiteknight T C E 15:17, 2 November 2005 (UTC)
 * Edited that template and made a new set of templates with snappier names, ability to name the inputs and outputs (with defaults A,B,C,Q) and an optional alignment parameter (defualts to centred). So far, there are templates for 1-, 2-, 3-input tables.
 *  gives:


 * Inductiveload (talk) 15:29, 30 April 2009 (UTC)

Standard for Boolean Symbols?
I teach a digital logic class at a community college and am interested in contributing to this book. I wondered, though, about the logic symbols used in Boolean expressions. While the symbols used in this text for AND, OR, and NOT are mathematically correct, several reference books I have on my shelf (along with the one I use in class) tend to use just common symbols found on a standard keyboard.

Could I suggest that we use the algebraic multiply for AND. Thus, to write "a AND b" we would write "ab" - just as multiply in algebra.

To write OR the algebraic "plus" is used. Thus, "a OR b" is "a + b".

Finally, a simple apostrophy is used for negation. Thus "a NOT OR b" would be "a' + b".

While this may not match some texts (and there seems to be a lot of variety on this standard), it is much easier to type Boolean terms on a standard keyboard using these symbols rather than the "V", overbar, and other symbols.
 * I've been through the page and changed to a style using just the AND = A·B, OR = A+B notation, rather than a mixture. The section on the two different notations stands, so readers will be warned about the other style. IMO, that style is more suitable for discrete mathematics and pure logic. We will be dealing with the practical implications, and thngs like sum-of-product are easier to understand in the times/add form (why do you think it is called sum-of-product rather that disjuntion of conjuction?)
 * While this page always uses the centre-dot to denote the multiplcation to keep it all unambiguous, after this page, I expect to use nothing, so A·B→AB.
 * As for negation, I quite like the overbar, as it extends to the whole expression being negated, and I find the apostrophe to look untidy (along with the exclamation mark). It also concerns me that a prime (usually written with just an apostrophe) is often used to denote things like "next state", and we don't want to tangle up the meanings. Remember there is always the ¬ symbol, which is designed for that use! Inductiveload (talk) 15:29, 30 April 2009 (UTC)


 * Mathematics courses tend to use one notation, and engineering courses tend to use the ⋅ and + notation.
 * The Overbar notation does simplify or eliminate lots of parentheses.
 * Note: for math students, 1 + 1 = 1 in boolean or digital logic context, so the + notation is similar to but not identical to traditional arithmetic. Nickalh (discuss • contribs) 12:11, 1 August 2023 (UTC)