Top 10 Light Emitting Diode Brand & Manufacturers

What is a Light Emitting Diode?

A Light Emitting Diode (LED) is a semiconductor device that emits light when an electric current passes through it. It is a type of diode, which means it has the characteristic of allowing current to flow in only one direction. LEDs are based on the principle of electroluminescence, where the recombination of electrons and holes in a semiconductor material results in the emission of photons, which we perceive as light.

History of the Light Emitting Diode

• The concept of electroluminescence dates back to the early 20th century. However, the first practical LED was developed in the 1960s. In 1962, Nick Holonyak Jr. at General Electric created the first visible - light - emitting diode, which emitted red light. This was a significant milestone in the field of electronics and lighting.
• Initially, LEDs had limited applications due to their low brightness and high cost. They were mainly used in indicator lights for electronic equipment such as calculators and digital watches. As the technology advanced, the brightness of LEDs increased, and their production costs decreased.
• In the 1990s and 2000s, the development of new semiconductor materials and manufacturing techniques led to the production of LEDs that could emit different colors, including blue and green light. The invention of the blue LED by Shuji Nakamura in 1994 was a crucial breakthrough, as it enabled the creation of white - light - emitting LEDs through a combination of red, green, and blue LEDs or by using a phosphor - converted blue LED. This led to the widespread use of LEDs in general lighting applications.

Applications of the Light Emitting Diode

• General Lighting: LEDs are now widely used in various lighting applications. They are used in residential lighting, such as in bulbs, lamps, and ceiling lights. In commercial settings, they are used in office lighting, retail store lighting, and in streetlights. The energy - efficiency and long lifespan of LEDs make them an ideal choice for replacing traditional incandescent and fluorescent lights.
• Indicator and Signal Lights: LEDs have been used for decades as indicator lights in electronic devices. They can be found in computers, printers, and other office equipment to indicate power status, data transfer, or other functions. In the automotive industry, LEDs are used for dashboard lights, brake lights, turn signals, and headlights, providing better visibility and energy - efficiency compared to traditional bulbs.
• Display Technology: LEDs play a crucial role in display applications. They are used in LED displays, such as those found in digital billboards, stadium scoreboards, and large - screen televisions. In liquid - crystal displays (LCDs), LEDs are often used as the backlight source, providing a more even and efficient illumination compared to traditional cold - cathode fluorescent lamps (CCFLs).
• Communication and Optoelectronics: LEDs can be used for optical communication, such as in fiber - optic data transmission. They are also used in optoelectronic sensors, where the light - emitting and light - detecting properties of LEDs are utilized to measure physical quantities such as distance, speed, or presence of objects.

Principle of the Light Emitting Diode

LEDs operate based on the principle of electroluminescence in a semiconductor p - n junction. When a forward - bias voltage is applied across the LED (i.e., the p - type semiconductor is connected to the positive terminal and the n - type to the negative terminal), electrons from the n - region are injected into the p - region, and holes from the p - region are injected into the n - region. At the p - n junction, the electrons and holes recombine. In the process of recombination, the electrons release energy in the form of photons. The energy of the photons determines the wavelength (and thus the color) of the light emitted. The wavelength is related to the energy bandgap of the semiconductor material used in the LED. For example, materials with a larger bandgap generally emit shorter - wavelength (higher - energy) light, such as blue or ultraviolet light, while materials with a smaller bandgap emit longer - wavelength (lower - energy) light, such as red or infrared light.

Features of the Light Emitting Diode

• Energy - Efficiency: LEDs are highly energy - efficient compared to traditional light sources. They convert a large percentage of the electrical energy into light energy, with much less energy wasted as heat. For example, an LED bulb can produce the same amount of light as an incandescent bulb while consuming a fraction of the power.
• Long Lifespan: LEDs have a much longer lifespan than incandescent and many fluorescent lights. A typical LED can last for tens of thousands of hours, reducing the need for frequent bulb replacements. This is especially beneficial in applications where changing bulbs is difficult or expensive, such as in high - ceiling lighting or in traffic lights.[!--empirenews.page--]
• Small Size and Design Flexibility: LEDs are very small in size, which allows for a high degree of design flexibility. They can be used in various shapes and configurations to create unique lighting designs. They can also be integrated into printed circuit boards and other electronic components easily.
• Fast Switching Speed: LEDs can turn on and off very quickly, which makes them suitable for applications that require rapid changes in light intensity or for use in communication systems where fast modulation of the light signal is needed.
• Color Variety: LEDs can be manufactured to emit a wide range of colors, including not only the visible spectrum but also infrared and ultraviolet light. This allows for creative lighting designs and the ability to use different colors for different functions or aesthetics.

Types of the Light Emitting Diode

• Visible - Light - Emitting Diodes: These are the most common type of LEDs and are used for lighting and indication purposes. They can emit different colors such as red, green, blue, yellow, and white. White - light - emitting LEDs can be further classified into different types based on the method of generating white light, such as phosphor - converted white LEDs and RGB (red - green - blue) white LEDs.
• Infrared - Emitting Diodes (IREDs): These LEDs emit infrared light, which is not visible to the human eye. IREDs are used in applications such as remote controls, infrared sensors, and night - vision equipment.
• Ultraviolet - Emitting Diodes (UV - LEDs): UV - LEDs emit ultraviolet light and have applications in sterilization, curing of adhesives and inks, and in forensic analysis.
• High - Power LEDs: These LEDs are designed to handle higher currents and produce more intense light. They are used in applications such as automotive headlights, high - intensity lighting fixtures, and industrial lighting.

Precautions for Using the Light Emitting Diode

• Current Limiting: LEDs have a specific forward - current rating, and exceeding this rating can damage the LED. Therefore, it is essential to use a current - limiting resistor or a proper current - regulation circuit to ensure that the current through the LED is within the specified range. For example, in a simple circuit with an LED and a power source, the value of the resistor can be calculated based on the supply voltage, the LED's forward - voltage drop, and the desired forward - current.
• Heat Sinking: Although LEDs are more energy - efficient than traditional light sources, they still generate heat. High - power LEDs, in particular, require proper heat - sinking to dissipate the heat and maintain their performance and lifespan. A heat sink is usually attached to the LED to conduct the heat away from the semiconductor junction.
• Reverse - Voltage Protection: LEDs are sensitive to reverse - voltage. Applying a reverse - voltage higher than the specified reverse - breakdown voltage can damage the LED. In a circuit, it is advisable to use a diode or other protection mechanisms to prevent reverse - voltage from being applied to the LED.
• Color Consistency: In applications where color consistency is important, such as in lighting fixtures or displays, it is necessary to select LEDs with a consistent color output. LEDs from different batches or manufacturers may have slight variations in color, so it is important to ensure that the LEDs used have the same or very similar color characteristics.

Considerations for Purchasing a Light Emitting Diode

• Application Requirements: Determine the specific requirements of your application, such as the desired light output (luminous flux), color, and beam angle. Consider whether you need a high - power LED for a bright lighting application or a lower - power LED for indication purposes. For example, if you are designing a reading lamp, you may need an LED with a high color - rendering index (CRI) and a suitable beam angle to provide good illumination.
• Type of LED: Based on your application needs, select the appropriate type of LED, such as a visible - light - emitting LED, an infrared - emitting LED, or a high - power LED. Consider the advantages and disadvantages of different types in terms of color, power, and application suitability. For instance, if you are building a remote - control device, an infrared - emitting LED would be the obvious choice.
• Performance Characteristics: Look at the forward - voltage drop, forward - current rating, luminous efficacy, and color - temperature characteristics of the LED. These performance characteristics should match the requirements of your application. A LED with a higher luminous efficacy will be more energy - efficient, while a specific color - temperature may be desired for certain lighting applications to create a particular ambiance.[!--empirenews.page--]
• Cost and Budget: Establish a budget for the LED purchase. The cost of LEDs can vary depending on their type, performance, and brand. Consider not only the initial purchase price but also the long - term costs such as energy consumption and potential replacement. Sometimes, a more expensive LED with better performance and reliability may be a more cost - effective choice in the long run.
• Manufacturer Support and Training: Select a reputable manufacturer that provides good technical support and training. Operating and using LEDs correctly may require some technical knowledge, and the manufacturer should offer resources such as user manuals, online tutorials, and customer support to help you get the most out of the LED.

Terms of the Light Emitting Diode

• Forward - Voltage Drop ($V_F$): The voltage across an LED when it is forward - biased and conducting current. It is an important parameter for calculating the current - limiting resistor value in a circuit.
• Forward - Current ($I_F$): The current flowing through an LED when it is forward - biased. The maximum forward - current rating indicates the maximum amount of current that the LED can safely conduct.
• Luminous Flux ($Phi_v$): A measure of the total amount of light emitted by an LED, in lumens. It represents the light - output capacity of the LED and is an important parameter for lighting applications.
• Color - Temperature: A characteristic that describes the color appearance of white - light - emitting LEDs. It is measured in Kelvin and ranges from warm (low - color - temperature) to cool (high - color - temperature) light, similar to the color of traditional incandescent or fluorescent lights.
• Color - Rendering Index (CRI): A measure of how accurately an LED can reproduce the colors of objects compared to a natural light source. A CRI of 100 represents perfect color - rendering, and a higher CRI is desirable for applications where accurate color - perception is important, such as in art galleries or in color - critical lighting.