ClassX Video Lessons Youtube Channel The Engineering Mindset How LED Works – Unravel the Mysteries of How LEDs Work!
Have you ever wondered why some LEDs glow red while others shine blue? It all comes down to the fascinating science behind Light Emitting Diodes, or LEDs. When you apply electricity to an LED, it lights up because of a tiny piece of semiconductor material inside. This material releases energy in the form of light particles called photons. Interestingly, if you shine light back onto an LED, it can generate a small amount of electricity in return!
LED stands for Light Emitting Diode. In technical drawings, LEDs are represented by a symbol similar to that of a diode, but with arrows indicating light emission. Both LEDs and regular diodes use semiconductor materials, but only LEDs emit visible light, which ranges from about 400 to 700 nanometers. The color of the light depends on the wavelength within this range.
Inside the semiconductor, electrons meet with holes, releasing photons and creating light. Regular diodes emit photons in the near-infrared range, which are not visible to us and are absorbed as heat. This is why diodes can get hot. LEDs, on the other hand, produce very little heat, making them much more energy-efficient compared to traditional light bulbs.
One of the most common types of LEDs is the five-millimeter through-hole LED, which has a flat edge on one side. These are great for learning electronics because they are inexpensive and easy to work with. You can find them in various sizes and designs, including surface mount devices (SMD) that are used for compact electronic designs.
LEDs are used in many applications, from flashlights to floodlights. When connecting an LED to a power source, it’s crucial to get the polarity right. The longer lead is the anode, and the shorter one is the cathode. If the leads are trimmed, the flat edge on the LED casing will help you identify the cathode side.
To prevent damage, it’s important to use a resistor when connecting an LED to a power source. The resistor limits the current flowing through the LED, ensuring it operates safely. You can find the recommended voltage and current for an LED in its datasheet, with most LEDs operating around 20 milliamps.
LEDs come in a variety of colors, determined by the semiconductor material used inside. The color of the LED casing doesn’t affect the light color; it’s all about the material within.
In summary, LEDs are efficient and versatile light sources that use semiconductor materials to produce light. They come in different designs and are used in a wide range of applications, making them an essential part of modern technology.
Gather a few LEDs, resistors, a breadboard, and a battery. Follow a circuit diagram to connect the components and light up the LEDs. Pay attention to the polarity and use resistors to protect the LEDs. This hands-on activity will help you understand how LEDs work in a circuit.
Use different colored LEDs and observe the light they emit. Discuss how the semiconductor material affects the color of the light. Try to identify the wavelength range for each color and relate it to the visible light spectrum.
Design and build your own flashlight using LEDs. Consider the type of LED, power source, and casing. This project will help you apply your knowledge of LED connections and explore practical uses of LEDs in everyday devices.
Test your understanding of LED polarity by connecting LEDs to a power source without guidance. Use the flat edge and lead length to determine the anode and cathode. This activity will reinforce your ability to safely connect LEDs.
Compare the energy efficiency of LEDs with traditional light bulbs. Measure the heat produced by each and discuss why LEDs are more energy-efficient. This experiment will deepen your understanding of the benefits of using LEDs.
Here’s a sanitized version of the provided YouTube transcript, with unnecessary details and promotional content removed for clarity:
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Why does this LED produce a red light while this one produces a blue light? When we apply a voltage across an LED, it emits light due to a tiny piece of semiconductor material inside that releases energy as photons. If we shine light onto the LED, we send photons back into it, reversing the process and producing a small voltage.
LED stands for Light Emitting Diode. In engineering drawings, we use a symbol for LEDs that resembles a diode symbol but includes arrows indicating light emission. Both LEDs and diodes operate on the same principle, utilizing semiconductor materials, but only LEDs emit photons in the visible range for humans, which is approximately 400 to 700 nanometers. Different colors correspond to different wavelengths within this range.
Inside the semiconductor, electrons combine with holes, releasing photons in the process. A standard diode uses different materials that produce photons in the near-infrared range, which are absorbed by the casing and converted to heat, causing diodes to become hot. In contrast, LEDs produce very little heat, making them more energy-efficient than traditional incandescent lights.
Most people recognize the common five-millimeter through-hole LED, which has a flat edge on one side. This design is useful for learning electronics, as these LEDs can be purchased cheaply in bulk. They can be inserted into test boards or soldered onto printed circuit boards. There are also smaller and larger versions available, as well as surface mount devices (SMD) that are soldered onto circuit boards for compact designs.
LEDs can produce bright light and are used in various applications, including torches and floodlights. However, when connecting an LED to a power source, it’s essential to ensure the correct polarity. The longest lead of the LED is the anode, while the shortest is the cathode. If the leads are trimmed, the flat edge on the LED casing indicates the cathode side.
When connecting an LED to a power source, we often use a resistor to limit the current and prevent damage. The resistor reduces the voltage supplied to the LED, allowing it to operate safely. The manufacturer’s datasheet provides the rated voltage and current for the LED, which is typically around 20 milliamps.
LEDs come in various colors, with the color produced depending on the semiconductor material used. The color of the LED casing does not determine the emitted light color; it’s the material inside that matters.
In summary, LEDs are efficient light sources that utilize semiconductor materials to emit light when powered, with various designs and applications available for different needs.
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This version focuses on the technical aspects of LEDs without promotional content or extraneous details.
Led – To guide or direct in a course – The teacher led the students through the process of building a simple electric circuit.
Semiconductor – A material that has a conductivity between that of an insulator and that of most metals, used in electronic devices – Silicon is a common semiconductor used in computer chips.
Photons – Particles representing a quantum of light or other electromagnetic radiation – When electrons move to a lower energy level, they emit photons, which we see as light.
Electricity – A form of energy resulting from the existence of charged particles – Electricity powers our homes and is essential for operating electronic devices.
Energy – The capacity to do work or produce change – In physics, energy can be transferred from one object to another, such as when a moving car hits a stationary object.
Diode – An electronic component that allows current to flow in one direction only – A diode is used in circuits to ensure that electricity flows in the correct direction.
Current – The flow of electric charge in a conductor – The current in the circuit was measured using an ammeter.
Resistor – A component used to resist the flow of current in a circuit – By adding a resistor to the circuit, the students were able to control the brightness of the LED.
Color – The property possessed by an object of producing different sensations on the eye as a result of the way it reflects or emits light – The color of the LED light can change depending on the material used in the semiconductor.
Applications – The practical uses of a scientific principle or device – The applications of semiconductors include their use in computers, smartphones, and solar panels.
