ASCENDING ORDER TIMER USING 7-SEGMENT DISPLAY A Seven Segment Display, 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, basic calculators, and other electronic devices that display numerical information.
The 7 segment display consists of seven LEDs (hence its name) arranged in a rectangular fashion as shown. Each of the seven LEDs is called a segment because when illuminated the segment forms part of a numerical digit (decimal numbers and some letters) to be displayed. An additional 8th LED (right corner) is sometimes used within the same package thus allowing the indication of a decimal point, (DP) when two or more 7-segment displays are connected together to display numbers greater than ten.Each one of the seven LEDs in the display is given a positional segment with one of its connection pins being brought straight out of the rectangular plastic package.
These individually LED pins are labelled from 'A' through to 'G' (see second image above) representing each individual LED. The other LED pins are connected together and wired to form a common pin.The displays common pin is generally used to identify which type of 7-segment display it is. As each LED has two connecting pins, one called the “Anode” and the other called the “Cathode”, there are therefore two types of 7 segment display called "common cathode - cc" and "common anode - ca" (see third image above).In this tutorial we will use a common cathode 7 segment display.