Understanding Seven-Segment Displays: Working, Implementation, and Applications, Essays (high school) of Business

Download Understanding Seven-Segment Displays: Working, Implementation, and Applications and more Essays (high school) Business in PDF only on Docsity! INTRUDUCTION Seven-segment display is a form of electronic display used for displaying alpha-numeric characters. A seven-segment display is a set of seven LEDs elements, arranged to form a figure of 8. Each of the LEDs is turned ON and OFF and the combination of LEDs which are ON forms a character. If all elements are activated, the display shows a numeral 8. Numbers from 0-9 and few alphabets can be displayed. The working of 7 segment display is on the similar lines as that of and LED as the 7 segment displays is eventually made up of 7 LEDs and an LED for the decimal point. The use of the decimal point is to display decimal numbers like 3.1 or 7.5. The 7 segment display are of two types viz. Common Anode display and Common Cathode display. COMMON ANODE DISPLAY IMPLIMENTATION All of the cathodes (negative terminals) or all of the anodes (positive terminals) of the segment LEDs are connected and brought out to a common pin; this is referred to as a "common cathode" or "common anode" device. Hence a 7 segment plus decimal point package will only require nine pins. Common cathode implementations require logic low (0) to turn on a segment, common anode implementations require logic high (1) to turn on a segment. BCD TO SEVEN SEGMENT CONVERSION The 7 segment displays are very popularly used in circuit boards and PCBs as display devices. This displays needs active nine pins of micro controller or other logic IC for driving it. And the scenario goes worst if multiple 7 segment displays are used. This makes the circuit bulky with many interconnections. To avoid this, it is essential to use a BCD to 7 segment display driver ICs like IC 7447 and IC 7448 in order to drive the displays. The inputs to the IC are 4 bit BCD value and the outputs are 7 pins which are connection to the 7 segment display. THE BCD VALUE CHART BCD Input Data SW3 SW2 SW1 SW0 Numeral Displayed 0 0 0 0 0