Q. Explain how LEDs are arranged in a seven segment display ?

The illustration given below shows the basic layout of the segments in a seven- segment display. The segments themselves are identified with lower-case letters "a" through "g," with segment "a" at the top and then counting clockwise. Segment "g" is the center bar.

Most seven-segment digits also include a decimal point ("dp"), and some also include an extra triangle to turn the decimal point into a comma. This improves readability of large numbers on a calculator, for example. The decimal point is shown here on the right, but some display units put it on the left, or have a decimal point on each side.

Seven-segment displays can be constructed using different technologies. The three most common methods are

1. fluorescent displays (used in many line-powered devices such as microwave ovens and some clocks and clock radios)

2. liquid crystal displays (used in many battery-powered devices such as watches and many digital instruments)and

3. LEDs (used in either line-powered or battery-powered devices).