A seven-segment display is commonly used in electronic display device for decimal numbers from 0 to 9 and in some cases, basic characters. Use of light emitting diodes (LEDs) in seven segment displays made it more popular, whereas of late liquid crystal displays (LCD) displays have also come into use. Electronic devices like microwave ovens, calculators, washing machines, radios, digital clocks etc. to display numeric information are the most common applications. Let’s take a look at the 7 segment display pinout to have a better understanding.
7 segment display pinout
A 7 segment display is made of seven different illuminating segments. These are arranged in a way to form numbers and characters by displaying different combinations of segments. The binary information is displayed using these seven segments. LED or light emitting diode is P-N junction diode which emits the energy in the form of light, differ from normal P-N junction diode which emits in the form of heat. Whereas LCD use properties of liquid crystal for displaying and do not emit the light directly. These LED’s or LCD’s are used to display the required numeral or alphabet.
Types of 7 segments
There are basically 2 types of 7 segment LED display:
Common Anode: All the Negative terminals (Anode) of all the 8 LEDs are connected together. All the positive terminals are left alone.
Common Cathode: All the positive terminals (Cathode) of all the 8 LEDs are connected together. All the negative thermals are left alone.
Working on 7 segments
Seven segment devices are generally made up of LEDs. These LEDs will glow when they are forward biased. The intensity of the LEDs depends on forward current. So, sufficient forward current has to be provided to these LEDs to glow with full intensity. This is provided by the driver and is applied to the seven segments.
|Number||g f e d c b a||Hex code|
Table: Display numbers on a seven segment display in common anode configuration
Things change for common cathode configuration.
|Number||g f e d c b a||Hex Code|
Table: Display numbers on a seven segment display in common cathode configuration
A sample interfacing of the 7 segment display to Arduino uno is provided for reference.
You can find some sample projects to work on involving 7 segment display here.