How LED Light Bulbs Work (2023)

How LED Light Bulbs Work (1)

The light bulb that has lit up our homes since the 1800s was officially on its way out after former President George W. Bush signed the Energy Independence and Security Act of 2007. Although the act didn't ban the use, purchase, sale or manufacture of incandescent bulbs, it did require household light bulbs to have 25 percent greater efficiency (which means 25 percent less energy use) than the traditional bulbs that used between 40 and 100 watts of electricity. The inefficient incandescent, where 90 percent of its energy is given off as heat, had fallen out of favor with the financially and ecologically concerned.

When the new lighting standards began in 2012, prime replacements for the incandescent light bulb were the higher-efficiency compact fluorescent lamps (CFL) and the light emitting diodes (LEDs). The CFL, though, has its own problems, primarily the inclusion of toxic mercury in the design and a strange, sometimes unpleasant color that even gives some people headaches.

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Enter the LED lights. LEDs have been around for many years — they light up digital clocks, Christmas lights, flashlights, traffic signals, etc. But as far as household lighting goes, LEDs weren't taking off. Certain drawbacks had kept companies from manufacturing them in standard, replacement-size light bulb form. But in the last decade or so, these LED replacement bulbs, the kind you just screw into a lamp like you do an incandescent bulb, have become much more common — which is to say a large number of businesses and households are using them.

A 2017 survey showed that 70 percent of Americans had bought at least one LED light bulb and 38 percent had switched over from incandescent bulbs to LEDs. This percentage has likely increased since 2017.

In this article, we'll look into how LED light bulbs work, why they're a desirable lighting choice, and some of the pros and cons surrounding them. Let's begin with the basics: How does an LED produce light?

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Contents

  1. LED Light Bulb Basics
  2. Advantages of LED Light Bulbs
  3. Concerns About LED Light Bulbs
(Video) How Modern Light Bulbs Work

LED Light Bulb Basics

An LED is what's called a "solid-state lighting" technology, or SSL. Basically, instead of emitting light from a vacuum (as in an incandescent bulb) or a gas (as in a CFL), an SSL emits light from a piece of solid matter. In the case of a traditional LED, that piece of matter is a semiconductor.

Stated very simply, an LED produces light when an electrical current passes through a microchip, which illuminates the tiny light sources called LEDs and the result is visible light. For a complete explanation, see How Light Emitting Diodes Work.

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The problem with LEDs as primary home lighting was that while they emit a lot of light, the structure of an LED caused some of that light to get trapped inside. So, an LED bulb was traditionally dimmer than an incandescent bulb, and most people want their lamps and ceiling fixtures to be pretty bright.

Now, LEDs bulbs have brightened up. You can now find LED replacement bulbs that emit light equivalent to a 60-watt incandescent light bulb or higher, which makes them a viable technology for basic lighting needs at home. And a LED replacement light bulb has a life 24,000 hours longer than that of a traditional incandescent 60-watt bulb.

And it's cheaper. Replacing your home's five most frequently used light bulbs with LED ENERGY STAR models, can save you $75 a year.

Which brings us to the pros and cons of LED light bulbs.

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(Video) What's Inside an LED Light Bulb

Advantages of LED Light Bulbs

How LED Light Bulbs Work (2)

First, there's the reduced energy use. The LED method of producing light uses far less energy to heat than do other lighting technologies. It's dramatically more efficient than the vacuum/filament method used in incandescent bulbs — using at least 75 percent less energy and it emits very little heat in comparison with incandescent bulbs (which release 90 percent of their energy as heat) and CFLs (which release about 80 percent of their energy as heat).

If you operate your lighting for 4,320 hours per year (360 hours per month/90 hours a week/12.85 hours a day), a 100-watt incandescent bulb would use 432 kilowatt-hours per year, while an equivalent 14-watt LED bulb would use just over 60 kilowatt-hours per year. LEDs also emit 90 percent less CO2 than the old halogens and 50 percent less than CFLs.

But energy efficiency is just part of the story. The other part is time efficiency: A good-quality LED bulb theoretically can have a life span of 25,000 hours or more, while incandescent bulbs have a 1,000-hour life span. Solid-state lights like LEDs are more stable light sources than incandescent or fluorescent bulbs, and the difference is startling: You'd have to leave a LED light on for 24 hours a day, seven days a week for three years before it matches an incandescent bulb's life span. (In fairness, not all LED light bulbs last as long as they can in theory. Some may have shorter life spans if parts wear out prematurely.)

Because of that time benefit, things get a bit more muddled when you get into the cost issue. A 60-watt LED replacement bulb runs in the area of $9.48 for a four-pack, while the same pack cost $3.97 for incandescent bulbs, according to Home Depot.

The reality is, even at $9.48 for a pack of four bulbs, LEDs will end up saving money in the long run, because you only need one every decade or two and you spend less money on home lighting, which can be six to seven times more energy efficient than incandescent lights and cut energy use by more than 80 percent.

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(Video) Here's Why You NEVER INSTALL LEDs IN YOUR CAR OR TRUCK!!

Concerns About LED Light Bulbs

LEDs are poised to take over household lighting. Philips has a collection of LED lights that includes color changes and Wi-Fi connected bulbs. And General Electric has a LED+ series that includes light bulbs with speakers, timers, color changes and more. It's estimated that LEDs will account for 75 percent of all lighting sales by 2030.

If you look at what the scientists are saying about LEDs, the picture does look pretty rosy. Breakthroughs are popping up at a breakneck pace. Except there's one problem.

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A growing number of studies have come out about the blue light that LEDs emit. Researchers say it may be damaging our eyes and health. A French health agency said it can damage the eye's retina while disturbing our biological rhythm and sleep disruption. The agency recommended limiting the use of LED devices with the highest blue-light content, especially for children. This would include computers, smartphones and other screens, as well as perhaps, certain toys and decorative lights.

The 2019 report confirmed the agency's 2010 results regarding the toxicity of blue light to the eye, which can lead to failing eyesight. "They show short-term phototoxic effects associated with acute exposure and long-term effects associated with chronic exposure, which increase the risk of developing age-related macular degeneration (ARMD)," the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) wrote in its report.

For more information about LED light bulbs and related topics, look over the links on the next page.

Originally Published: Jul 23, 2009

LED Light Bulbs FAQs

How LED light bulbs work?

An LED produces light when electrons move around within its semiconductor structure. A semiconductor is made of a positively charged and a negatively charged component. The positive layer has "holes" -- openings for electrons; the negative layer has free electrons floating around in it. When an electric charge strikes the semiconductor, it activates the flow of electrons from the negative to the positive layer. Those excited electrons emit light as they flow into the positively charged holes.

What are the advantages of LED bulbs?

LED bulbs consume less power than other lighting technologies. They are also energy-efficient, safe to use and have a longer life. Compared to incandescent light sources, LED bulbs are 85% more energy efficient.

Can LED lights be left on all the time?

Yes, LED lights are ideal for places where light needs to be left on all the time. You don’t have to worry about high electricity bills because LED bulbs consume low power and generate less heat.

Do LED lights burn out?

Typically, LED lights can last for up to 25,000 hours. However, just like other electronic components, LED lights may burn out before that, due to extreme voltage fluctuations or premature part failures.

Does turning LED lights on and off shorten their life?

No, turning the LED light on and off doesn’t shorten its operating life. This usually happens with fluorescent bulbs. What really shortens the life of LED bulbs is overheating. So, make sure you don’t have electricity fluctuations to prevent overheating the LEDs.

(Video) Should you choose LED or HID Bulbs? Everything you need to know!

(Video) Two failed LED bulbs for teardown to determine the cause

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FAQs

How does a LED light bulb work? ›

LED stands for light emitting diode. LED lighting products produce light up to 90% more efficiently than incandescent light bulbs. How do they work? An electrical current passes through a microchip, which illuminates the tiny light sources we call LEDs and the result is visible light.

How does an LED work simple explanation? ›

A light-emitting diode (LED) is a semiconductor device that emits light when an electric current flows through it. When current passes through an LED, the electrons recombine with holes emitting light in the process.

Do LED lights give enough light? ›

For starters, LED bulbs last much, much longer than incandescent bulbs, and they put out the same amount of light using significantly less energy . That's great for the environment, and it can save you money on your electricity bill in the long term, especially if you're upgrading a whole home's worth of bulbs.

What is LED short answer? ›

A Light Emitting Diode (LED) is a semiconductor device, which can emit light when an electric current passes through it. To do this, holes from p-type semiconductors recombine with electrons from n-type semiconductors to produce light.

How does it work light bulb? ›

Essentially, the lightbulb is a very thin filament of hard-to-melt metal – tungsten, usually – encased in a glass bulb filled with inert gases so that the filament doesn't oxidise and disintegrate. The electricity causes the wire to glow and a portion of that energy is turned into light.

How does a light work? ›

Light exhibits characteristics of both waves and particles, the latter of which are described as packets of energy called photons. These waves, or photons, travel in narrow beams called rays. Only when light rays move from one medium to another, such as from air to water, are their linear paths altered.

Why are LED lights more efficient? ›

LEDs are the most efficient form of lighting

LEDs use much less energy to provide the same amount of light as other forms of lighting. One of the main reasons LEDs are so efficient is that most of their energy is used to solely create light, rather than creating light and heat, as less efficient forms of lighting do.

How do LED lights save energy? ›

LEDs use much less energy than incandescent bulbs because diode light is much more efficient, power-wise, than filament light. LED bulbs use more than 75% less energy than incandescent lighting. At low power levels, the difference is even larger.

What makes LED lights brighter? ›

LED lights are so bright because they have a high lumen/watt score. Lumens are the measure of the total quantity of visible light emitted. Here is an illustration that demonstrates the difference between a low lumen count and a high lumen count.

How much light do LED lights produce? ›

Depending on the bulb and the manufacturer, LED technology typically produces 75-110 lumens/watt. So, LEDs are generally about 7 times more efficient at producing light than incandescent bulbs.

Do LED bulbs give more light? ›

Efficiency of LED Lighting

LEDs are more than five times as great as their incandescent counterparts. They use only about 20 percent as much electricity to product the same amount of light.

What is an LED made of? ›

LEDs are comprised of compound semiconductor materials, which are made up of elements from group III and group V of the periodic table (these are known as III-V materials). Examples of III-V materials commonly used to make LEDs are gallium arsenide (GaAs) and gallium phosphide (GaP).

What is LED with example? ›

Short for light-emitting diode, LED is a semiconductor that illuminates when an electrical charge passes through it. LEDs are commonly green, amber, or red, but they can be an assortment of other colors as they've become popular with case lighting. Below are examples of how an LED could be used with a computer.

How do LED lights work chemistry? ›

When a current is applied to the LED, the electrons in the n-type layer and the electron 'holes' in the p-type layer are driven to an active layer between the two. When the electrons and electron 'holes' combine, energy is released, and this is seen as visible light.

How a light bulb works step by step? ›

The incandescent light bulb consists of a thin tungsten filament inside of an inert gas-filled glass bulb. When electricity is applied across the filament, electrons begin to flow. These electrons encounter resistance from the tungsten material, and in turn produce energy as they collide. This energy turns into heat.

How do you make a light bulb work? ›

Light the bulb using two wires. Attach one wire to the negative end of the battery and wrap the other end of the same wire around the base of the bulb. Attach the other wire to the positive end of the battery with electrical tape and to the base of the bulb, completing the circuit and lighting the bulb.

What makes the bulb light up? ›

The typical incandescent light bulb contains a thin wire (usually tungsten) called a filament that has a high electrical resistance. This filament gets very hot when an electric current passes through it. The intense temperature makes the filament glow brightly.

Why do we need light answer? ›

Light allows us to see the surrounding world by distinguishing details, individual colours, movement, brightness. It has a very big impact on a human in terms of the physiology and psyche. But light also has extremely important functions in relation to a lot of biological processes that occur in our body.

What is light in simple way? ›

Light is defined as the electromagnetic radiation with wavelengths between 380 and 750 nm which is visible to the human eye.

What is light made of? ›

Light is made of particles called photons, bundles of the electromagnetic field that carry a specific amount of energy. With sufficiently sensitive experiments, you can count photons or even perform measurements on a single one. Researchers have even frozen light temporarily.

Are LED lights 100% efficient? ›

While energy conversion efficiency of incandescent lamps is between 10 and 20 percent, highly efficient LEDs currently achieve values between 40 and 50 percent.

How efficient is a LED? ›

Switch to LEDs

LEDs use about 75% less energy than halogen light bulbs and last 5 to 10 times longer, greatly reducing replacement costs and the number of light bulbs ending up in landfill. The up-front cost of LEDs generally has a payback time of less than 1 year.

Why LED is more efficient device than a bulb? ›

LEDs emit almost no forward heat while traditional bulbs like incandescents convert more than 90% of the total energy used to power them directly into heat. That means only 10% of the energy powering incandescent lights is actually used for light (which also makes them extremely inefficient compared to LEDs).

How much energy does an LED bulb save? ›

For example, a 60W halogen light bulb would be replaced with a 9W LED. That's a reduction of 85% in electricity consumption. The LED bulb will also last for over 20,000 hours, as opposed to 2,000 hours for the halogen – ten times longer!

How long do LED lights last? ›

The average lifespan of an LED is often rated up to 50,000 hours. This is about 50 times longer than a typical incandescent, 20-25 times longer than a typical halogen and 8-10 times longer than a typical CFL. If used 12 hours a day, an LED rated at 50,000 hours will last more than 11 years.

How much energy does an LED bulb use? ›

The average 60-watt equivalent LED light bulbs uses . 01 kWh of electricity per hour it's on. In comparison the equivalent incandescent bulb . 06 kWh of electricity per hour.

Why are my LED lights so dark? ›

LED bulbs can lose their brightness due to premature aging, bad internal components like a capacitor or LED arrays, or the common cause of loose wiring. Heavy load appliances on the circuit can also cause that LED lights are dim.

How do you increase the brightness of an LED? ›

There are two methods for adjusting the brightness of the LED:
  1. Modify the value of the resistor. Simply connect a potentiometer in series with the LED to change the brightness by adjusting the resistor value. ...
  2. Quickly switch it on and off. Another technique is to quickly turn the LED on and off.
27 Jul 2021

Why do my LED lights stay on dim? ›

You might notice that LED lights tend to stay or at times dim even when the off switch has been toggled. This is usually due to the residual current left behind.

What voltage do LED bulbs use? ›

Typically, the forward voltage of an LED is between 1.8 and 3.3 volts. It varies by the color of the LED. A red LED typically drops around 1.7 to 2.0 volts, but since both voltage drop and light frequency increase with band gap, a blue LED may drop around 3 to 3.3 volts.

What energy does LED lights use? ›

The electricity used by a light bulb is measured by KWh. An LED bulb uses 127.5KWh over its lifespan of 15,000 hours. Incandescent bulbs used for 15,000 hours (for theoretical purposes; an incandescent bulb cannot last that long) will use up 900KWh of electricity.

Why do LED bulbs glow when turned off? ›

So let's get rolling. Why Do LED Bulbs Glow When Off? An LED bulb, compared to halogen lamps or incandescent bulbs, has a much higher resistance on count of the integrated power supply unit. What happens is that the serial connection of the glow lamp clamps the circuit even when you turn the switch off.

Which is better bulb or LED? ›

LED bulbs require much less wattage than CFL or Incandescent light bulbs, which is why LEDs are more energy-efficient and longer lasting than their competitors.

Do LED bulbs get brighter the longer they are on? ›

LEDs are often described as an instant kind of light since they achieve full brightness as soon as they are turned on. This means that LEDs do not gradually get brighter, as most LEDs can reach full brightness in less than 500 milliseconds.

Are there lights better than LED? ›

XED lights are better in terms of spectral contents, power consumption as well as total running life hours. They produce less glares and are clearer under foggy weather. Moreover, the XED lights don't have excess blue emissions like LED lights.

What is inside a LED bulb? ›

It's called solid-state lighting because unlike incandescent and fluorescent lighting technologies, there are no gases involved in LEDs. Instead, energy is passed through a semiconductor (usually a solid chemical element or compound that can conduct electricity), lighting up the LED light bulb.

Does LED have electricity? ›

LEDs consume far less electricity than incandescent bulbs, and decorative LED light strings such as Christmas tree lights are no different.

What are the 3 types of LED light bulbs? ›

Fundamentally, there are three different types of LED technology that are used in LED lighting – DIP, SMD and COB.

How is LED made? ›

Alloy LED - How LED's Are Made - YouTube

What is the full meaning of LED? ›

LED, in full light-emitting diode, in electronics, a semiconductor device that emits infrared or visible light when charged with an electric current.

What is the difference between LED and LED? ›

LCD is the abbreviation for liquid crystal display while LED is the abbreviation for light-emitting diodes.
...
Difference between LCD and LED
LCDLED
LCDs are usually thicker and lack energy efficiency compared to LEDs.LEDs are much thinner and are much more energy-efficient.
4 more rows
29 Nov 2021

How do LEDs produce color? ›

LEDs produce different colors by using various materials which produce photons at different wavelengths. Those individual wavelengths appear as light of different colors. LEDs use materials that can handle the necessary levels of electricity, heat, and humidity.

What is the difference between a regular light bulb and an LED? ›

LEDs use much less energy than incandescent bulbs because diode light is much more efficient, power-wise, than filament light. LED bulbs use more than 75% less energy than incandescent lighting. At low power levels, the difference is even larger.

What is inside an LED light bulb? ›

It's called solid-state lighting because unlike incandescent and fluorescent lighting technologies, there are no gases involved in LEDs. Instead, energy is passed through a semiconductor (usually a solid chemical element or compound that can conduct electricity), lighting up the LED light bulb.

How does an LED get power? ›

The simplest way to power an LED is to use a DC constant voltage source that is already powering other electronics in the circuit. Current can be controlled with a series resistor. See Figure 3. This is inexpensive and convenient, especially if power is already being supplied to other components.

How do LED lights change color? ›

LEDs produce different colors by using various materials which produce photons at different wavelengths. Those individual wavelengths appear as light of different colors. LEDs use materials that can handle the necessary levels of electricity, heat, and humidity.

Can I replace normal bulb with LED? ›

Replacing your existing incandescent or halogen bulbs with durable LED bulbs offers numerous benefits. You enjoy an even better light performance and benefit from very low energy consumption. Furthermore, LEDs can handle all hues of white light, so the warm yellowish light of halogen bulbs is perfectly within reach!

What is the disadvantage of LED light? ›

Perhaps the biggest drawback of LED light bulbs is that they emit more blue light than incandescent bulbs, which are more on the red end of the spectrum. Blue light can cause a disruption in your circadian rhythm, negatively affect your ability to fall asleep and the quality of your sleep.

Can you put a LED bulb in a regular fixture? ›

As long as the mounting base (socket) is the same size and type, you can use an LED bulb in an existing fixture. If the mounting base isn't the same size and type, the LED bulb will not fit the socket. You should never use a bulb with a higher wattage than what is recommended for the fixture.

Which gas is used in LED bulb? ›

A mixture of six inert gases (helium, neon, argon, krypton, xenon, and nitrogen) was introduced as the filling gas of LED bulb.

Which material is used in LED? ›

The material used most often in LEDs is gallium arsenide, though there are many variations on this basic compound, such as aluminum gallium arsenide or aluminum gallium indium phosphide.

Are LED light bulbs glass or plastic? ›

LED bulbs are made of hard durable plastic, making them almost indestructible. Something to keep in mind is how much you can save on your power bill. LED bulbs use 90% LESS electricity vs your traditional glass incandescent bulb.

Do LED lights work when the power is out? ›

The bulbs have the ability to store energy from the power grid and use it when they need it, even if the grid is offline at the time. SmartCharge LED light bulbs are created to fit into existing lamps and fixtures just like any other LED replacement bulb.

What voltage do LED lights use? ›

Typically, the forward voltage of an LED is between 1.8 and 3.3 volts. It varies by the color of the LED. A red LED typically drops around 1.7 to 2.0 volts, but since both voltage drop and light frequency increase with band gap, a blue LED may drop around 3 to 3.3 volts.

What type of energy does LED use? ›

An LED, or Light Emitting Diode, is a type of solid-state lighting that uses a semiconductor device to convert electricity into light. The electrical current passes through a microchip, illuminating the LEDs and results in visible light.

What are the types of LED? ›

Fundamentally, there are three different types of LED technology that are used in LED lighting – DIP, SMD and COB.
  • Dual In-Line Package (DIP) LEDs. DIP LED Lights. ...
  • Surface Mounted Diode (SMD) LEDs. SMD LED Spotlight Bulb. ...
  • Chip on Board (COB) LEDs. COB LED Spotlight Bulb.
10 Oct 2017

Why do LED lights stay one color? ›

If your LED strips are stuck on one color when you change colors, it's probably because you have been pressing the same color button, which reaches peak value. Try using the reverse button to adjust it higher or lower. If still to no avail, check the contact of your pins and reconnect.

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4. How does an LED work at the molecular AND practical level? | Intermediate Electronics
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5. LED Explained
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6. LED working & advantages | Semiconductors | Physics | Khan Academy
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