Page "Logic gate" Paragraph 11

There are two sets of symbols for elementary logic gates in common use, both defined in ANSI / IEEE Std 91-1984 and its supplement ANSI / IEEE Std 91a-1991.

The " distinctive shape " set, based on traditional schematics, is used for simple drawings, and derives from MIL-STD-806 of the 1950s and 1960s.

It is sometimes unofficially described as " military ", reflecting its origin.

The " rectangular shape " set, based on IEC 60617-12 and other early industry standards, has rectangular outlines for all types of gate and allows representation of a much wider range of devices than is possible with the traditional symbols.

The IEC's system has been adopted by other standards, such as EN 60617-12: 1999 in Europe and BS EN 60617-12: 1999 in the United Kingdom.