Display Devices 7 segment led display

What is 7-segment LED Display? 7-segment LED Display is display device which can display one digit at a time Actually one digit is represented by arrangement of 7 LEDs in a small cubical box For representing 3 digit number we need three 7-segment LED Displays

How it look like?

Internal Structure There are two types of 7-segment LED Display Common Cathode Common Anode

Common Cathode

How to glow the segments? We need to provide +5 V to other open ends to turn ON that particular segments We need to provide 0 V to other open ends to turn OFF that particular segments

How to print 2 on LED Display? To show 2 on LED display then you must illuminate A, B, G, E and D segments of the display. So you must give voltages on pins 10, 9, 8, 5, 4, 2, 3 and 7 in Common cathode slide as High, High, Low, High, High, Low, High and Low respectively for drawing 2 on display

Common Anode

How to glow the segments? We need to provide +5 V to other open ends to turn OFF that particular segments We need to provide 0 V to other open ends to turn ON that particular segments

How to print 3 on LED Display? To make 3 on display then you must illuminate A, B, C, D and G segments of the display. So you must give voltages on pins 10, 9, 8, 5, 4, 2, 3 and 7 in figure 4 as High, High, High, High, Low, Low, High and Low respectively for drawing 3 on display

BCD to 7 segments Decoder

Inputs and Outputs of BCD to 7 segment decoder

Pin Out of Common Anode LED Display

Interfacing with ATmega8

Multi Digit 7 segments LED Display (Multiplexing)

Circuit diagram for multiplexing

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