dotmatrix

Dot matrix is a term used to describe technologies that render images or characters by arranging a grid of small dots. It is most commonly applied to dot matrix printers and dot matrix displays, where images are formed by turning individual dots on or off.

Dot matrix printers use a print head with an array of pins that strike ink from a ribbon onto paper. As the print line is formed, patterns of pins create characters and graphics as a mosaic of dots. Most models use 9- or 24-pin heads and offer resolutions from about 60 to 240 dots per inch, with speeds measured in characters per second. They are inexpensive and robust, support multipart forms, but produce grainy output and are noisy compared with modern printers.

Dot matrix displays arrange a grid of light-emitting or liquid-crystal elements. A bitmap is mapped to the grid, turning on or off individual dots to render text or simple graphics. Common sizes include 5×7 and 8×8 matrices; larger arrays can display longer text or images. They are cheap, low-power, and easy to drive, making them popular in embedded devices, signage, and hobby projects.

Historically, dot matrix concepts were foundational in early computing and signage. While most consumer devices use higher-resolution imaging today, the dot matrix approach persists in embedded displays and specialized printers, and remains associated with retro computing. See also dot matrix printer and dot matrix display.