A 7-segment display is an assembly of light emitting diode-bars (segments) each which can be powered individually. They are arranged and labeled as shown in the diagram, in the form of an '8' in hexadecimal form. When all the segments are powered on, the display show the number 8. Powering up segments a, b, c, d, and g will display the number 3. Each individual 7-segment can display numbers from 0 to 9. The 'dot' or dp represents the decimal point, which can be selected either on the left or right side of the display.

It's possible to adjust the brightness of the digits on the display. When the display is first turned on, it uses a mid-range level which is a good compromise between brightness and battery drain.

The LED number display can show 16-bit values in a hexadecimal format. This is useful for displaying numbers outside of the 0 to 9999 decimal range, or for displaying values that are easier to read if show in hex.

The LED number display has a mode that lets you decide exactly which segments to light up. This lets you make arbitrary patterns or display alphabetic-style information.They are widely used for instruction of moving taxis,buses or gas stations.