Talk:Subtractor

Can the Subtracter (electronics) be explained with circuits and truth tables the same way as the Adder (electronics)(http://en.wikipedia.org/wiki/Full_adder)?


 * a subtractor is basically just an adder with one input inverted and the first carry in set to 1 rather than 0.

Full Subtractor
the truth table for full subtractor is not correct; read this => http://www.doc.ic.ac.uk/~dfg/hardware/HardwareLecture13.pdf  60.48.175.38 (talk) 18:57, 26 September 2011 (UTC)

Note, the full substractor graphic is wrong. The first inversor goes in the A imput. If the subtrahend is 0 and the minuend is 1, it triggers the borrow out. — Preceding unsigned comment added by Mbertelotti (talk • contribs) 20:42, 22 April 2013 (UTC)

Half subtractor diagram
The diagram should be replaced such that the X input is the minuend and Y is the subtrahend. Doing it this way would make the diagram consistent with the article and the following explanation unnecessary:

An important point worth mentioning is that the half subtractor diagram aside implements $$Y - X$$ and not $$X - Y$$ since $$B_\text{out}$$ on the diagram is given by
 * $$B_{\text{out}} = X \cdot \overline{Y}$$.

This is an important distinction to make since subtraction itself is not commutative, but the difference bit $$D$$ is calculated using an XOR gate which is commutative.

We could still have a footnote that says whichever input is inverted is the minuend. --Usability (talk) 07:40, 1 November 2015 (UTC)