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Series No:BL-D40E-21
Specification Download:
20.1 × 16 × 7 mm
0.40 inch double numeric LED display

The Evolution of Display Technology: 0.40 Inch Dual-Digit Seven Segment LED Display

In the rapidly evolving world of electronics, the 0.40 inch dual-digit seven segment LED display has carved out a significant niche. Known for its compactness and efficiency, this display technology, often referred to as the 8 seg display or double 7 segment display, combines traditional readability with modern efficiency. This article dives deep into the features, applications, benefits, and the real-world impact of these displays, drawing on case studies and user testimonials to provide a comprehensive overview.

The Anatomy of an 8 Seg Display

At its core, the 8 seg display revolutionizes how information is presented in a limited space. Unlike the more common seven-segment display, the double 7 segment display integrates an additional segment for more nuanced character representation. This slight variation opens up new possibilities for displaying characters and symbols, enhancing user interface experiences.

Key Features of the 0.40 Inch Display

The 0.40 inch dual-digit seven segment LED display stands out for several reasons:
  • Compact Size: Ideal for applications where space is at a premium.
  • High Brightness: Ensures visibility even in well-lit conditions.
  • Energy Efficiency: Consumes less power, making it suitable for battery-operated devices.
  • Versatility: Capable of displaying numbers, some letters, and symbols.

Applications Across Industries

This display finds its place in a myriad of applications, from consumer electronics like digital clocks and calculators to more specialized equipment in healthcare and automotive industries. Its ability to convey information clearly and concisely makes it a valuable component in any electronic system requiring a digital readout.

Advantages for Electronics Manufacturers

The benefits of incorporating the 0.40 inch dual-digit seven segment LED display into electronic devices are manifold:
  • Reduced Power Consumption: Extends the battery life of portable devices.
  • Improved Product Design: Enhances aesthetic appeal with a modern look.
  • Increased Reliability: Offers longevity and durability even in harsh conditions.

Case Studies: Demonstrating Value

The impact of these displays is best understood through real-world examples. Case studies from various sectors, including consumer electronics and industrial applications, illustrate how the 0.40 inch dual-digit seven segment LED display has been instrumental in improving device functionality and user satisfaction.

User Testimonials: Insights from the Field

Feedback from engineers, purchasers, and end-users who have interacted with these displays provides a ground-level view of their advantages. Testimonials highlight the displays' reliability, ease of integration, and the overall enhancement of product value they facilitate.

The Future of Seven Segment Displays

Looking ahead, the 0.40 inch dual-digit seven segment LED display, along with emerging technologies like the 11 segment display and 7 bit segment display, promise to push the boundaries of what's possible with electronic displays. Innovations in materials, lighting efficiency, and programmability are expected to broaden their applications and appeal further.

Conclusion: Lighting the Way Forward

The 0.40 inch dual-digit seven segment LED display represents a blend of traditional utility and modern innovation, making it an essential component in the design and manufacturing of electronic devices. Its versatility, efficiency, and reliability make it an excellent choice for anyone looking to enhance their electronic products.

Call to Action

For electronics professionals seeking to incorporate cutting-edge display technology into their projects, the 0.40 inch dual-digit seven segment LED display offers a compelling combination offeatures and benefits. Explore the possibilities today to elevate your products to the next level.
0.40 inch dual-digit seven segment led display
0.40 inch dual-digit seven segment led display


  • 0.40 Inch Digit Height (10.20mm): Offers clear and visible numeric displays, suitable for applications where compactness and readability are key.
  • Compact Dimensions: Measuring 20.10 x 16.00 mm, it's ideal for small-scale applications where space is at a premium.
  • Low Current Operation: Energy-efficient design, which is particularly beneficial in battery-operated or power-sensitive devices.
  • Common Anode and Common Cathode Availability: Provides flexibility in electronic design, accommodating different types of circuit configurations.
  • Excellent Character Appearance: Ensures sharp and clear numeric displays for ease of readability.
  • High Light Output: Bright display ensures visibility under various lighting conditions.
  • Easy Mounting on PC Boards or Sockets: Simplifies the process of integration onto printed circuit boards or into sockets, easing assembly.
  • IC Compatible: Can be easily interfaced with various integrated circuits, suitable for complex electronic systems.
  • Multicolor Availability: Available in different colors, offering options for customization and various design requirements.
  • Categorized for Luminous Intensity: Ensures uniform brightness across units for consistent performance.
  • Technically Rugged: Durable and reliable, built to withstand various operational conditions and environments.
  • Standard Design: Features a standard gray surface with white segments, offering a classic and clear display appearance.
  • RoHS Compliance: Manufactured in compliance with environmental and health safety standards.


  • Digital Clocks and Timers: Ideal for timekeeping devices in various settings such as schools, offices, or kitchen appliances.
  • Electronic Scoreboards: Suitable for sports arenas and event venues for displaying scores, times, or other numerical information.
  • Industrial Equipment: Used in machinery for displaying measurements, counts, or operational data.
  • Consumer Electronics: Incorporated in appliances like microwave ovens, washing machines, and other household devices for setting displays.
  • Medical Devices: Employed in medical equipment for showing readings, timers, and numerical data.
  • Automotive Displays: Applicable for displaying information on car dashboards, such as temperature, fuel level, or other indicators.
  • Control Panels: Used in control panels for machinery, HVAC systems, and industrial systems for clear numeric readouts.
  • Telecommunication Equipment: Suitable for network devices and communication equipment for displaying numeric information.
Dimension and Circuit Drawing:
Related Information


When soldering, leave a minimum of 2mm clearance from the base of the base of the lens to the soldering point. Dipping the lens into the solder must be avoided.

Do not apply any external stress to the lead frame during soldering while the LED is at high temperature.

Recommended soldering conditions:


IR Reflow Soldering (for SMD display)Wave SolderingSoldering Iron
Pre-Heat150-180°CPre-Heat100°C Max.Temperature300°C Max.
Pre-Heat Time120sec Max.Pre-Heat Time60sec Max.
Peak Temperature260°C Max.SolderWave260°C Max.Soldering Time3sec Max.(one time only)
Soldering Time10 sec Max.Soldering Time5sec Max.

Note: Excessive soldering temperature and/or time might result in deformation of the LED lens or failure of the LED

ESD(Electrostatic Discharge)

Static Electricity or power surge will damage the LED.

Suggestions to prevent ESD (Electrostatic Discharge):

n Use a conductive wrist band or anti-electrostatic glove when handling these LEDs

n All devices, equipment, and machinery must be properly grounded

n Work tables, storage racks, etc. should be properly grounded

n Use ion blower to neutralize the static charge which might have built up on surface of the LED’s

 plastic lens as a result of friction between LEDs during storage and handling

ESD-damaged LEDs will exhibit abnormal characteristics such as high reverse leakage current, 

low forward voltage, or “no light on” at low currents. To verify for ESD damage, check for “light on” 

and Vf of the suspect LEDs at low currents.

The Vf of “good” LEDs should be>2.0V@0.1mA for InGaN product and >1.4V@0.1mA for AlInGaP


antistatic notice-smd led

When selecting power for LED systems, it’s essential to understand several key parameters to ensure safe operation, longevity, and optimal performance. Here are some steps and considerations for LED power selection:

  • Determine the Forward Voltage (Vf) of the LED(s):

Each LED has a forward voltage, which is the voltage at which the LED operates when the current is flowing through it. This value can typically be found in the LED’s datasheet.

  • Determine the Forward Current (If) of the LED(s):

The forward current is the current at which the LED is designed to operate. Running an LED at higher than its rated current can reduce its lifespan and increase the heat it produces.

  • Decide on the Configuration:

Series Configuration: When LEDs are connected in series, the forward voltages add up, but the current remains the same.

Parallel Configuration: When LEDs are connected in parallel, the forward voltage remains the same, but the currents add up. This configuration can be risky because if one LED fails or has a slightly lower forward voltage, it can cause the other LEDs to draw more current.

Calculate Total Power Requirements:

Power (W) = Total Forward Voltage (V) x Total Forward Current (A)

For example, if you have three LEDs connected in series, each with a forward voltage of 3V and a forward current of 20mA, the total power requirement would be:

Power = (3V + 3V + 3V) x 20mA = 9V x 0.02A = 0.18W

  • Select an Appropriate Power Supply:
  • Voltage Rating: The power supply voltage should match or slightly exceed the total forward voltage of your LED configuration.
  • Current Rating: The power supply’s current rating should meet or exceed the total forward current of your LED configuration.
  • Safety Margin: It’s a good practice to select a power supply that can provide at least 20% more power than your calculated requirement. This ensures the power supply isn’t operating at its maximum capacity, which can extend its life and ensure safer operation.
  • Consider Additional Features:
  • Dimming Capability: If you want to control the brightness of your LEDs, choose a power supply with dimming capabilities.
  • Overcurrent and Overvoltage Protection: To protect your LEDs, select a power supply with built-in protection mechanisms.
  • Thermal Management: Ensure that the power supply has adequate cooling, especially if it will be enclosed or in a location with limited airflow.
  • Regulation and Efficiency:A power supply with good regulation will maintain a consistent voltage output despite variations in the load. High efficiency ensures minimal power is wasted as heat.
  • Physical Size and Form Factor:Depending on where you plan to place the power supply, its size and shape may be critical factors.

In summary, when selecting power for LED systems, understanding your LED’s requirements and the configuration you plan to use is essential. Then, pick a power supply that meets those needs with some added safety margin, keeping in mind any additional features or constraints relevant to your project.

Here are some well-regarded brands in the industry:

  • Mean Well: One of the most recognized brands in the LED power supply industry, Mean Well offers a wide range of products suitable for both indoor and outdoor applications. Their units often come with features like overcurrent protection, dimming capabilities, and high efficiency.
  • Tridonic: A global leader in lighting technology, Tridonic offers LED drivers and power supplies that cater to various lighting solutions, from simple setups to advanced smart lighting systems.
  • Philips Advance Xitanium: Philips is a well-known brand in the lighting industry, and their Xitanium series of LED drivers are known for reliability and performance. They cater to both indoor and outdoor LED applications.
  • Osram: Another giant in the lighting industry, Osram offers a range of LED drivers and power supplies suitable for various applications, including architectural and street lighting.
  • LIFUD: Specializing in LED drivers, LIFUD is known for its high-quality products that cater to both commercial and residential LED lighting solutions.
  • MOSO: This brand offers a variety of LED drivers, especially for outdoor and industrial applications. Their products are known for durability and performance.
  • TDK-Lambda: With a history in power electronics, TDK-Lambda offers a range of power supplies and LED drivers suitable for various applications, emphasizing reliability and advanced features.
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