A 7-segment display is commonly used in electronic display devices for decimal numbers from 0 to 9 and in some cases, basic characters. The use of light-emitting diodes (LEDs) in seven-segment displays made it more popular, whereas of late liquid crystal displays (LCD) 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 seven display pinout to have a better understanding.
7-Segment Display Pinout
A seven-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.
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The binary information is displayed using these seven segments. LED is a P-N junction diode that emits energy in the form of light, different from a standard P-N junction diode which emits in the form of heat.
Whereas LCD uses liquid crystal properties for displaying and does not emit light directly. These LEDs or LCDs are used to display the required numeral or alphabet.
7-Segment Display Types
There are basically 2 types of seven-segment LED displays:
1. Common Anode 7 Segment Display:
All the Negative terminals (Anode) of all the 8 LEDs are connected together. All the positive terminals are left alone.
2. Common Cathode 7 Segment Display:
All the positive terminals (Cathode) of all the 8 LEDs are connected together. All the negative thermals are left alone.
Seven-Segment Display Working
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 the forward current.
So, a 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.
7-Segment Display Codes
The below table shows the 0-9 codes for the seven-segment LED display.
Number
g f e d c b a
Hex code
0
1000000
C0
1
1111001
F9
2
0100100
A4
3
0110000
B0
4
0011001
99
5
0010010
92
6
0000010
82
7
1111000
F8
8
0000000
80
9
0010000
90
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
0
0111111
3F
1
0000110
06
2
1011011
5B
3
1001111
4F
4
1100110
66
5
1101101
6D
6
1111101
7D
7
0000111
07
8
1111111
7F
9
1001111
4F
Table: Display numbers on a seven-segment display in common cathode configuration
Below we are interfacing a 7-segment display to Arduino UNO for reference.
7-Segment Display-based Projects
Dice with seven segment display
Water level indicator
For more technical information, you can refer to the7-Segment Display Datasheet.
FAQs:
What is a 7-segment display?
A 7-segment display is a visual indicator used to display numerical digits and some characters. It consists of seven LED segments arranged in a specific pattern, with each segment representing one of the digits from 0 to 9.
How does a 7-segment display unit work?
Each segment in a 7-segment display is individually controlled to turn on or off. By selectively activating specific segments, you can form the desired digit or character. For example, to display the digit ‘5’, you would activate the segments necessary to create its visual representation.
How do I get a 7-segment display?
You can obtain a 7-segment display from electronics suppliers, online marketplaces, or local electronic component stores. They are available in various sizes, colors, and configurations to suit your project’s requirements.
What is the objective of a 7-segment display?
The main objective of a 7-segment display is to provide a simple and visually recognizable way to display numerical information. It’s commonly used in digital clocks, calculators, digital meters, and other applications where numerical data needs to be presented.
How does a 7-segment display work?
Each segment in a 7-segment display corresponds to a specific LED or segment, with the arrangement designed to form the digits 0 to 9 when activated in different combinations. By turning on the required segments, you create the desired number or character on the display.
Are seven-segment displays still in production?
Yes, seven-segment displays are still in production and widely used in various applications. They offer a cost-effective and straightforward solution for displaying numeric information and are often integrated into digital devices and electronic projects.
This article was first published on 29 December 2016 and recently updated on August 2023.
In most practical applications, 7-segment displays are driven by a suitable decoder/driver IC such as the CMOS 4511 or TTL 7447 from a 4-bit BCD input.
The 12 pins of the seven-segment display can be grouped into two types: segment pins and digit select (scan) pins. The current limiting resistors are to protect the LED in each of the segments. There are four digits and there are eight segments for each digit (including the decimal point).
The 4-digtal 7-segment display works independently. It uses the principle of human visual persistence to quickly display the characters of each 7-segment in a loop to form continuous strings. For example, when “1234” is displayed on the display, “1” is displayed on the first 7-segment, and “234” is not displayed.
The circuit can be used as a clock. In this circuit the counter will advance after one minute or after every one second depending on the value of resistor selected. It can be used while cooking or while doing exercise or by students preparing for competitive exams.
The seven elements of the display can be lit in different combinations to represent each of the Arabic numerals. The individual segments are referred to by the letters "a" to "g", and an optional decimal point (an "eighth segment", referred to as DP) is sometimes used for the display of non-integer numbers.
The CD4511 chip is essentially a BCD to 7-Segment decoder/driver IC, with which you can convert a binary number into a decimal number on the 7-segment display. For example, printing the number “2” on 7-segment display will require giving 0010 to the input pins (A,B,C,D) of the CD4511 chip.
The basic idea involves driving a common cathode 7-segment LED display using combinational logic circuit. The logic circuit is designed with 4 inputs and 7 outputs, each representing an input to the display IC. Using Karnough's map, logic circuitry for each input to the display is designed.
It is made up of seven segments labeled as (a,b,c,d,e,f,g) which are placed in a specific pattern, where each segment represents a different part of the number.
In common anode mode, the LED display provides RGB LEDs with a unified voltage higher than 3.8V (such as 5V), therefore the power consumption is high. In common cathode mode, the LED display provides RGB LEDs with separate voltage based on actual needs (2.8V for the red LED, and 3.8V for the green and blue LEDs).
each display unit is usually has a dot point (DP). The display point could be located either towards the left or towards the right of the display pattern. This type of pattern can be used to display numerals from 0 to 9 and letters from to F hexadecimal digits.
Seven-segment displays may use a liquid crystal display (LCD), a light-emitting diode (LED) for each segment, or other light-generating or control techniques such as cold cathode gas discharge (Panaplex), vacuum fluorescent, incandescent filaments (Numitron), and others.
A seven-segment display is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot matrix displays. Seven-segment displays are widely used in digital clocks, electronic meters, basic calculators, and other electronic devices that display numerical information.
A digital or binary decoder is a digital combinational logic circuit which can convert one form of digital code into another form. BCD to 7-segment display decoder is a special decoder which can convert binary coded decimals into another form which can be easily displayed through a 7-segment display.
Introduction: My name is Kareem Mueller DO, I am a vivacious, super, thoughtful, excited, handsome, beautiful, combative person who loves writing and wants to share my knowledge and understanding with you.
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