Semiconductor light-emitting diodes

Hello, I have a revision question regarding the stability of an LED operating at a fixed current versus one operating at a fixed voltage. The effect of device heating on IV characteristics and the conditions for positive or negative feedback are also considered. In summary, it is more stable to fix the current for an LED because small changes in current won't cause large changes in voltage. Further research is needed to understand the temperature effects on the equations for light output versus junction current and current versus junction voltage. It is important to note that an LED is a current-controlled device.
  • #1
smn
13
0
Hello, i have a revision question that I'm only part-able to answer.
The question is:
Explain why an LED operating at a fixed current would be more stable than one operating at a fixed voltage.Consider the effect of the device heating on the IV characteristics.Explain under which condition there would be positive or negative feedback from the from the heating.
What i can answer:
If an LED is operating at a fixed voltage, then only small changes in voltage will result in large changes in current.Therefore it's better to fix the current because small changes in current won't cause large changes in voltage.
If anyone could point me in the right direction for the other parts it will be much appreciated.
Regards
 
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  • #2
Start with the equation for light output versus junction current. Look at any temperature related effects in that equation, and then look at the equation for the current versus junction voltage and the temperature effects there.
 
  • #3
This might require more research, but isn't a diode a current-controlled device?

MLH
 

What are semiconductor light-emitting diodes?

Semiconductor light-emitting diodes (LEDs) are electronic devices made from materials such as silicon or gallium arsenide, which can emit light when an electric current is passed through it. They are widely used in various lighting and display applications due to their energy efficiency and long lifespan.

How do semiconductor light-emitting diodes work?

When an electric current is passed through the semiconductor material, electrons and holes (positively charged vacancies) are formed. When these two particles combine, energy is released in the form of photons, which are particles of light. The color of the light emitted depends on the type of semiconductor material used.

What are the advantages of using semiconductor light-emitting diodes?

Semiconductor LEDs have several advantages over traditional incandescent or fluorescent bulbs. They are more energy efficient, have a longer lifespan, and do not contain hazardous materials such as mercury. They also have the ability to emit light in a specific direction, making them more efficient for certain applications.

What are some common applications of semiconductor light-emitting diodes?

Semiconductor LEDs are commonly used in various lighting applications, including streetlights, traffic lights, and household lighting. They are also used in electronic displays, such as televisions and computer screens. Additionally, they are used in automotive lighting, medical devices, and even in aerospace technology.

What advancements have been made in semiconductor light-emitting diode technology?

Over the years, there have been significant advancements in semiconductor LED technology. These include improvements in energy efficiency, color range, and brightness. There have also been developments in the production process, making LEDs more affordable and widely available. Research is ongoing to further enhance the performance and capabilities of these devices.

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