Last Updated on April 27, 2023 by Prepbytes
The seven segment display was first introduced in the late 1950s by engineers at RCA (Radio Corporation of America). It was initially used in industrial equipment and test and measurement instruments. The seven segment display is important because it allows for the display of numerical information.
Introduction to Seven Segment Display
A seven segment display is a type of electronic component that can be used to display numerical information in a digital format. It is made up of seven individual segments, which can be lit up in different combinations to create the appearance of numbers from 0 to 9. The segments are arranged in a rectangular shape and can be controlled by an electronic circuit or microcontroller. This type of display is commonly used in digital clocks, calculators, and other electronic devices where numerical information needs to be displayed. All seven segments of the seven segment display are labelled from English alphabets A to G. Let’s see how these seven segments are arranged in a rectangular pattern.
In the above example, there is a total of 7 segments arranged in a rectangular pattern to form the seven segment display. Some of these or all of the segments are turned on to generate a particular digit or some letter.
How a Digit is Formed Using the Seven Segment Display?
To form a digit using the seven segment display, we can turn on some or all of the segments out of the seven segments. Now, we will see how some digits are formed using this seven segment display.
Let’s see how 0 is formed using the seven segment display.
In the above image, we can see that we have turned on the segments A, B, C, D, E, and F to form the digit 0.
Let’s see how 9 is formed using the seven segment display.
In the above image, we can see that we have turned on the segments A, B, C, D, F, and G to form the digit 9.
Representation of All Digits using Seven Segment Display.
All digits from 0 to 9 can be displayed using the seven segment display. Here, is the representation of all digits using seven segment display:
In the above images, we have formed all the digits using the seven segment display.
Truth Table of the Seven Segment Display
Now, we will see the truth table to display digits from 0 to 9 in the Seven Segment Display.
In the above seven segment display truth table, 1 represents that the segment is on and 0 represents that the segment is off. For example, to form the digit 1, segments B and C are on while segments A, D, E, F, and G are off. To control the Seven Segment Display various types of microcontrollers require such as switches, keypads, and memory.
Types of the Seven Segment Display
There are two common types of seven segment displays:
- Common Cathode Seven Segment Display
- Common Anode Seven Segment Display
1. Common Cathod Seven Segment Display
In this type of display, all the cathodes of the seven segments are connected together and are supplied with a negative voltage, while each segment’s anode is individually controlled by the microcontroller or the driver circuit. When a voltage is applied to the cathode, all of the segments are turned off. To turn on a specific segment, a voltage is applied to its corresponding anode pin, causing it to light up.
2. Common Anode Seven Segment Display
In this type of display, all the anodes of the seven segments are connected together and are supplied with a positive voltage, while each segment’s cathode is individually controlled by the microcontroller or the driver circuit. When a voltage is applied to the anode, all of the segments are turned on. To turn off a specific segment, a voltage is applied to its corresponding cathode pin, causing it to turn off.
Applications of the Seven Segment Display
Here, are the applications of the seven segment display:
- Digital clocks: It is an electronic device that displays the time numerically in the form of digits, usually using LED or LCD technology. Digital clocks are commonly used in homes, offices, schools, and public places.
- Clock radios: It is a combination of a clock and a radio, which allows the user to listen to music or news while also keeping track of the time. Clock radios often have features like alarms, snooze buttons, and AM/FM radio tuning.
- Calculators: It is an electronic device used to perform mathematical calculations. Calculators come in various types, including basic, scientific, graphing, and financial calculators. They are widely used in schools, universities, and workplaces.
- Wristwatches: It is a portable timepiece that is worn on the wrist. It typically consists of a clock face, a strap, and a mechanism that keeps time. Wristwatches can be analogue or digital, and they are commonly used for personal timekeeping and as a fashion accessory.
- Speedometers: It is an instrument that measures and displays the speed of a vehicle. It is typically located on the dashboard of a car or motorcycle and uses various methods to measure the speed, such as a mechanical cable or electronic sensors.
- Motor-vehicle odometers: It is an instrument that measures the distance travelled by a vehicle. It is typically located on the dashboard of a car or motorcycle and uses various methods to measure the distance, such as a mechanical cable or electronic sensors.
- Radiofrequency indicators: It is a device that detects the presence and strength of radiofrequency signals in the environment. It is commonly used in radio communications, radar systems, and electronic warfare to detect and identify the signals emitted by other devices. Radiofrequency indicators can be analogue or digital, and they are often portable and handheld.
In conclusion, the seven-segment displays are simple and cost-effective display devices that are widely used to display numerical information. They are easy to control and can be used in a variety of electronic devices. With the help of a decoder IC, they can be easily integrated into electronic circuits to display any desired numerical or alphabetical information.
FAQs Related to Seven Segment Display
Q1. What are the segments in a seven-segment display called?
Ans: The seven segments in a seven-segment display are labeled A, B, C, D, E, F, and G.
Q2. Can a seven-segment display form negative numbers or decimals?
Ans: No, a seven-segment display can only display the decimal digits 0 through 9, as well as a few letters. It cannot display negative numbers or decimals.
Q3. How are the segments of a seven-segment display lit up?
Ans: The segments of a seven-segment display are lit up by passing a current through them. This can be done using light-emitting diodes (LEDs), liquid crystal displays (LCDs), or other lighting elements.
Q4. Are there alternatives to seven-segment displays?
Ans: Yes, there are alternatives to seven-segment displays, including dot-matrix displays, character displays, and graphical displays. These alternative displays offer higher resolution and the ability to display more complex information, but they are typically more expensive and complex to control than seven-segment displays.
Q5. How do you troubleshoot a faulty seven-segment display?
Ans: If a seven-segment display is not working properly, the first step is to check the connections to make sure they are secure and the correct voltage is being applied. If the connections are fine, the next step is to check the individual segments for faults using a multimeter. If a segment is faulty, it can be replaced or the entire display can be replaced if necessary.
Q6. What are the advantages of using a seven-segment display?
Ans: The advantages of using a seven-segment display include its simple, low-cost, and versatile design, making it a popular choice for a wide range of applications that require the display of numerical information.
Q7. How do you control a seven-segment display?
Ans: Seven-segment displays can be controlled using a decoder IC (integrated circuit) that takes a binary input and decodes it to the corresponding number or letter to be displayed on the seven-segment display. The individual segments are turned on by connecting the corresponding cathodes (in a common anode display) or anodes (in a common cathode display) to ground or a positive voltage.
Q8. What are the different types of seven-segment displays?
Ans: There are two types of seven-segment displays: common anode and common cathode. In a common anode display, all the anodes (positive terminals) of the LEDs are connected together, while in a common cathode display, all the cathodes (negative terminals) of the LEDs are connected together.