Seven segment Displays are very common when it comes to display digits, these are widely used in clocks, stop watches and event counter etc. A Simple seven segment display is shown in the image below..
This is a front view..
![seven_segment_display](/images/seven_segment_display.jpg)
And this is back view...
![seven_segment_display_back](/images/seven_segment_display_back.jpg)
The seven segment display as the name implies consist of 7 Leds, these 7 leds together can form any number from 0 to 9 as shown below..
![seven_segment_display_count](/images/seven_segment_display_count.gif)
Below is shown a model where 7 leds are placed in such a way that they can form any digit..
![seven_segment_display_model](/images/seven_segment_display_model.jpg)
This seven segment display is a 10 pin component.. these pins are basically for each LED, for decimal LED (DOT which is shown above) and also for ground/power connection.