Seven Segment

A seven-segment display, or seven-segment indicator, is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot-matrix displays. Seven-segment displays are widely used in digital clocks, electronic meters, and other electronic devices for displaying numerical information.

Concept and visual structure

A seven segment display, as its name indicates, is composed of seven elements. Individually on or off, they can be combined to produce simplified representations of the arabic numerals. Often the seven segments are arranged in an oblique (slanted) arrangement, which aids readability. In most applications, the seven segments are of nearly uniform shape and size (usually elongated hexagons, though trapezoids and rectangles can also be used), though in the case of adding machines, the vertical segments are longer and more oddly shaped at the ends in an effort to further enhance readability.

Each of the numbers 0, 6, 7 and 9 may be represented by two or more different glyphs on seven-segment displays.

  The seven segments are arranged as a rectangle of two vertical segments on each side with one horizontal segment on the top, middle, and bottom. Additionally, the seventh segment bisects the rectangle horizontally. There are also fourteen-segment displays and sixteen-segment displays (for full alphanumerics); however, these have mostly been replaced by dot-matrix

displays.

The segments of a 7-segment display are referred to by the letters A to G, as shown to the right, where the optional DP decimal point (an "eighth segment") is used for the display of non-integer numbers.

The animation to the left cycles through the common glyphs of the ten decimal numerals and the six hexadecimal "letter digits" (A–F). It is an image sequence of a "LED" display, which is described technology-wise in the following section. Notice the variation between uppercase and lowercase letters for A–F; this is done to obtain a unique, unambiguous shape for each letter (otherwise, a capital D would look identical to an 0 (or less likely O) and a capital B would look identical to an 8).

Seven segments are, effectively, the fewest required to represent each of the ten Hindu-Arabic numerals with a distinct and recognizable glyph. Bloggers have experimented with six-segment and even five-segment displays with such novel shapes as curves, angular blocks and serifs for segments; however, these often require complicated and/or non-uniform shapes and sometimes create unrecognizable glyphs