Seven Segment Displays

Seven Segment Displays
Seven Segment Displays

Seven-segment displays are electronic devices that display numbers or characters. Their seven LED segments form a “8” shape, with the eighth section being a dot or decimal point. These displays are popular due to their simplicity, low cost, and electronic circuit integration. They are used in digital clocks, calculators, temperature displays, and panel meters. Seven segment displays’ definition, history, applications, and operating principles will be examined in this paper.

Seven-segment displays can display decimal digits (0-9) and alphanumeric characters by lighting up seven segments. Segments can be controlled separately to make numerals and characters. A, b, c, d, e, f, and g are the traditional segments, with ‘a’ being the uppermost and ‘g’ the middle horizontal. These displays can be common anode or cathode depending on whether the power supply’s positive or negative terminal is shared by all segments. For basic, unambiguous numerical or character displays, seven-segment segment displays are popular.

A seven-segment display?

Seven-segment displays show decimal numerals. It has seven switching light-emitting LEDs or liquid crystal display segments to display 0–9.

It Works How?

The seven parts indicate digits. Display the arabic numerals 0–9 by illuminating segments in different configurations. To show ‘2’, light up segments a, b, g, e, and d. To display ‘3’, light a, b, g, c, and d.

Common Types

Two types of seven-segment displays are common:

LEDs are used as light sources. LED screens are brilliant but power-hungry.

• LCD (liquid crystal display) blocks light. Backlit LCDs use less power but are harder to read in bright light.

In common anode or cathode pinouts. Pinout refers to the LED or LCD segment’s connection side. Knowing this helps control the display.


Electronics projects, appliances, clocks, and counters employ seven-segment displays for numerical data. Some examples are:

  • Digiclocks
  • Timers
  • Calculators
  • Voltage, current, temperature, etc. electronic meters


They make displaying numbers via a visual electronic interface easy and affordable. Seven segment displays are straightforward to use and suitable for many applications, but not as adaptable as dot matrix displays.

You can display numbers quickly if you understand seven segment displays and their types and functions! If you have any further questions regarding using seven segment displays in projects, let me know.

Seven-Segment Display History

Seven Segment Displays began as mechanical displays in the early 1900s. Electronic versions were developed in the mid-20th century. The first solid-state seven-segment displays used incandescent or neon bulbs in the 1950s. LEDs replaced the bulbs, improving visibility, reliability, and energy efficiency. The seven segment display has evolved to encompass compact surface mount, dot matrix, and bigger outdoor displays. Their history is linked to LED technology and the need for clear and efficient numerical representations.

Seven-Segment Display Applications

Seven-segment displays are used in consumer and industrial devices. Digital clocks, microwave ovens, calculators, and other equipment use them as number indicators. Automotive speedometers, fuel gauges, and temperature displays use seven section displays. Industrial control panels, medical equipment, and measurement tools use these displays. Seven segment displays are ideal for numerical or character-based visual applications due to their clear numeric output. Their inexpensive cost and easy integration into electronic circuits make them popular throughout sectors.

Anode vs. cathode seven-segment displays

Choose between common cathode and common anode displays for seven segment displays. The internal wiring of LEDs makes the difference.

A Common Cathode

A common cathode seven-segment display connects all LED cathodes (negative terminals). To ignite a segment, provide positive voltage to its anode. Only one cathode pin is needed because cathodes are common. Common cathode displays are cheaper and more accessible.

Common Anode

A common anode seven-segment display connects all LED anodes (positive terminals). To light a section, connect its cathode (negative terminal) to ground. Additional pins are needed for common anode displays.

Your microcontroller or driver circuit must be compatible when choosing a display. Common cathode displays are driven by most microcontrollers. Find a compatible driver or install inverter circuitry to use a common anode display.

The option depends on availability, cost, and driver circuit compatibility. Common cathode displays work well for most seven-segment display designs and simplify things. You can easily develop an interface for either type with a few more components if you need to use a common anode display.

Understand how the two types differ to know what modifications to do to appropriately illuminate those seven LED segments!

Seven-Segment Display Wiring

Seven-segment display wiring is simple. You’ll need these basics to begin:

  • A 7-segment display
  • A power supply (3-5V DC)
  • About 220 ohm resistors
  • Jumper cables

Connecting Segments

The seven segments (a-g) must be linked to the positive or ground rail. Use jumper wires to connect each of the display’s seven pins to power or ground via a resistor.

To show ‘0’, connect segments a, b, c, d, e, and f to power and g to ground. Try different combinations to display 0–9.

After practice, you can build custom characters and symbols. Endless possibilities!

Multiple Displays

Connect the ground and positive voltage pins of several seven segment displays to utilize them together. Connect each segment’s jumper wires in parallel.

  • Attach: To display ’12’ on two monitors, attach:
  • A–f to power
  • Section g to ground
  • on the first screen, and
  • B, C power segments
  • Parts a–g to ground
  • on exhibit 2.

Others to Consider

Be aware of your power supply’s current rating. Multiple displays and segments can pile up quickly because each illuminated segment draws little current.

Additional current-limiting resistors (about 220 ohms) in series with each segment may avoid shorts or overcurrent damage.

Have fun and be creative with seven-segment displays! Any questions? Let me know.

Arduino Seven-Segment Display Control

Arduino control of a seven-segment display is simple. To begin, you need:

Arduino Uno/compatible board

Common cathode 7-segment display

8 220 ohm resistors

Jumper wires, breadboard

Display connection

All 7 segments (A-G) and the decimal point have their own Arduino pins.

Connect pin A to digital pin 2 and the rest to digital pins 3–10. Digital pin 11 can link to decimal point pin DP.

Connect each segment pin to its Arduino pin with a 220 ohm resistor. This prevents display current overload.

Next, connect the Arduino’s “COM” cathode to ground. The common cathode grounds all segments.

Controlling display with code

You may now light up segments and display numbers using simple code.

void setup() { For (int i=2; i<=11; i++) { pinMode(i, OUTPUT); // Set pins 2-11 as outputs

void loop() { // Show 0
DigitalWrite(2, HIGH); DigitalWrite(3, HIGH); DigitalWrite(4, HIGH); DigitalWrite(5, HIGH); DigitalWrite(6, HIGH); delay(1000);

Display 1: digitalWrite (2, LOW); digitalWrite(3, HIGH); delay(1000);

For Display 2, use digitalWrite(2, HIGH); digitalWrite(3, HIGH); digitalWrite(4, LOW); digitalWrite(5, HIGH); digitalWrite(6, HIGH); delay(1000);

Continuing to display numbers…

This code lights up the 7-segment display to show 0–9. Create entertaining displays with letters, symbols, or short words and phrases. Arduino beginners can control a 7-segment display. Have more questions? Let me know!

Seven-Segment Display Applications and Projects

Seven-segment displays are entertaining and handy for DIY electronics projects. Here are some starter ideas:

Digital Clock

Digital clocks are popular introductory seven-segment display projects. It takes four seven-segment screens to show hours, minutes, and seconds. Use an Arduino to program the displays to track time and update. Learning multiplex displays, button input, and simple scripting with this project is fantastic.


Create a simple up/down counter to tally people entering a room, goals scored, etc. Two seven-segment displays, some incrementing and decrementing buttons, and a microcontroller are plenty. Microcontroller reads button presses and updates display count. Basic digital input and output reading and control are taught in this project.


Seven-segment screens and a temperature sensor make a digital thermometer. Connect the sensor to your microcontroller to read and show temperature on the seven segments. The thermometer can be calibrated for Celsius or Fahrenheit. This project introduces analog sensor reading and scaling/calibrating.


For a more sophisticated project, build a simple calculator with seven section displays. Eight digit screens and number and operation buttons are needed. Program your microcontroller to read button pushes, calculate, and display results. This teaches mathematical expression parsing and operator precedence logic.

Seven-segment displays are useful for electronics and coding practice. Start with a small project and progress to more complicated projects as you learn. There are so many fun and useful things you can make!


You now understand seven-segment displays and how to design a basic circuit. These common components are easy to use and offer many possibilities for basic electronics projects. Seven-segment screens may display numbers, letters, and special characters. Grab some monitors and other components and start making something awesome. You know how—now make something that lights up and shows off your new skills. Bright prospects! You might invent the next must-have device with a seven-segment display. The future is unwritten—write code and solder electronics!

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