Table of Contents
About 7 segment display:
Seven segment displays are the output display device that provides a way to display information in the form of an image or text or decimal numbers. It consists of seven segments of light-emitting diodes (LED s) which are assembled like numerical 8. Since seven segment displays can not form an alphabet like X and Z, so it can not be used for the alphabet and it can be used only for displaying decimal numerical magnitudes. However, seven-segment displays can form alphabets A, B, C, D, E, and F, so they can also use for representing hexadecimal digits. The Working of Seven Segment Displays is explained below.
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/7-seg.png?resize=480%2C360&ssl=1)
Checking 7-Segment Display with Multimeter
Testing individual segments of a 7 Segment display:
seven-segment displays will have a CC mark for the common cathode and a CA mark for the common anode.
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/image-16.png?resize=422%2C290&ssl=1)
The above figure shows both the variants of 7 segment displays i.e the common anode and common cathode.
Steps involved in testing:
- Hold the display in your hand and identify pin 1.
- Now take the multimeter (assuming a red lead for positive and a black lead for negative) and Keep the multimeter in diode mode shown in the below picture.
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/image-17.png?resize=190%2C366&ssl=1)
- Put your multimeter red lead on pin 3 or 8 as shown in the figure.
- Now put your meter’s black lead on any other pin such as 1,2,3,4 or 5 as shown in the figure.
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/image-18.png?resize=499%2C212&ssl=1)
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/image-19.png?resize=355%2C236&ssl=1)
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/image-20.png?resize=355%2C236&ssl=1)
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/image-21.png?resize=355%2C236&ssl=1)
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/image-22.png?resize=358%2C218&ssl=1)
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/image-23.png?resize=358%2C234&ssl=1)
- If any of the display’s segments glow then the display is a common anode.
- Connect your meter’s black lead to pin 3 or pin 8.
- Now put the red lead of the multimeter on another remaining pin as shown in the figure. If any of the segments glow then the display is a common cathode, as in a common cathode the negative pin is common and the rest are connected to a positive supply.
![](https://i0.wp.com/mevihub.com/wp-content/uploads/2022/04/image-24.png?resize=412%2C237&ssl=1)
- Check all segments of both common cathode and anode to ensure the display is working properly.
- If no segment glows, this 7 segment is faulty.