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Why do led lights flicker – Everything you need  to know 

Why do led lights flicker


In the realm of modern lighting, the subtle dance of LED lights flickering holds secrets that often go unnoticed by the naked eye. Whether it's the warm glow of incandescent bulbs, the efficiency of halogens, the hum of fluorescent tubes, or the brilliance of LED illumination, all mains-powered light sources partake in this rhythmic flickering. In the United Kingdom, where mains electricity flows as alternating current (AC) at a frequency of 50 hertz, the electric current powering lights engages in a remarkable back-and-forth journey, oscillating a remarkable 50 times per second. In the days of old incandescent bulbs, this flickering eluded our attention, masked by the residual heat that sustained the filament's glow between pulses. The inefficiency of traditional bulbs, wasting nearly 90 percent of input energy as heat, inadvertently concealed this phenomenon. However, today, the age of LED lighting heralds a new era, debunking the misconception that flickering can be evaded by maintaining a constant power input. As we delve into the captivating realm of LED flicker, the heart of this discussion beats with the mission to unravel the hidden truths behind this phenomenon and provide a clearer understanding of its implications for the world of lighting.

LED Flicker and the Unveiling Truth

The narrative of LED flicker transcends mere illumination—it's a journey into the interplay between technology and electricity supply. Contrary to popular belief, LED flicker is not solely a result of the LED's internal mechanisms; rather, it's intimately linked with the very nature of the electricity coursing through our homes. With the transition from incandescents to LEDs, the veil has been lifted, revealing the intricacies of the flicker phenomenon. While LEDs are designed to operate more efficiently than their incandescent counterparts, the consistent current supplied by the alternating current (AC) grid can lead to variations in luminance over time. This can manifest as visible flicker, causing discomfort and even health concerns. The quest to understand and mitigate this phenomenon requires a journey into the realms of electrical engineering, technology design, and consumer education.

A New Dawn of Awareness

As the world embraces the energy-efficient marvels of LED lighting, awareness about LED flicker has emerged as a pivotal concern. In the past, the incandescent bulb's inefficiency masked the flicker, but the LED's swift response time and sensitivity to current variations have brought the phenomenon to the forefront. The implications are vast, extending beyond aesthetic discomfort to potentially impacting health, visual acuity, and even the performance of digital imaging devices. With the proliferation of LED lighting across diverse settings, from cozy homes to bustling workplaces, understanding and addressing LED flicker has become paramount. The pursuit of a flicker-free LED experience requires collaboration between researchers, manufacturers, and consumers to optimize lighting designs, minimize flicker effects, and foster a future where the brilliance of LEDs is unmarred by the subtleties of fluctuating electric currents.


In the symphony of illumination, LED flicker represents a chapter that demands exploration and enlightenment. Beyond being a mere technical quirk, LED flicker unveils the intricate relationship between technology and the electrical currents that power our lives. Armed with knowledge, we stand at the threshold of better lighting solutions that illuminate spaces without casting the shadows of discomfort or health concerns. As we journey through this enlightening discourse, we aim to demystify LED flicker, foster awareness, and forge a path toward a brighter, more constant future in lighting—an era where the harmonious dance of LEDs remains undisturbed by the unseen rhythms of electricity.

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Why Some People Perceive Flickering LEDs as a Concern

LED lighting has come a long way, but there's still a misconception about LED flicker. In the past, flickering LEDs were a prevalent issue due to their unique nature. Unlike traditional incandescent, halogen, or fluorescent lights, LEDs lack persistence. When an LED receives power, it lights up instantly, but when power is cut off, so is the light output. When directly connected to an AC mains-electricity supply, LEDs can switch on and off up to 50 times per second, leading to visible flicker. This is why some individuals believe that LEDs flicker more than older light sources. However, the situation has evolved over time. Modern LED installations have found a solution to this challenge. Instead of directly connecting LEDs to the mains supply, they are now powered using specialized LED drivers. These drivers effectively eliminate flicker issues associated with direct connections. Today, LED flicker is not a concern for contemporary LED projects, providing a smoother and more consistent lighting experience. As technology has advanced, the worry about LED flicker has been addressed through innovative solutions, ensuring optimal illumination quality and reducing any perceived problems related to flickering lights.


In the world of LED lighting, the persistent issue of LED flicker has been a cause for concern. To truly understand and combat this problem, it's essential to recognize that LEDs operate on direct current (DC) power, as opposed to alternating current (AC). The key to eradicating LED flicker lies in the quality of the power supply you employ to drive your LED lights. Often referred to as 'LED transformers' in the industry, these power supplies do more than just step down voltage; they convert current from mains AC to DC. Opting for a high-quality LED power supply ensures a steady and constant current supply to your LEDs, resulting in a seamless, flicker-free lighting experience.

In contrast, lower-quality LED drivers simply convert AC to DC without maintaining a constant current. This basic conversion method generates an oscillating current, typically doubling the input-voltage frequency, which in the UK can lead to a frequency of 100 potential flickers per second. While this might seem problematic, the average human eye is generally unable to perceive flickers occurring at such a rapid rate. Most individuals only register fluctuations in light at frequencies well below 100 flickers per second, typically around 50 or slower. For reference, computer screens typically operate within the range of 60 to 70 hertz, which most of us barely notice.

Therefore, for the majority of lighting installations, a basic, no-frills LED 'transformer' suffices. In fact, there are even scenarios where LED flicker can be considered a desirable effect, such as in nightclubs or with oscillating bicycle lights. So, the next time you wonder about the flickering of your LED lights, remember that the key lies in selecting a high-quality LED power supply, ensuring a constant and flicker-free illumination that meets the needs of various applications.


While a basic LED power supply can get the job done, for more demanding projects, a constant-current power supply is the way to go. These advanced LED drivers excel in virtually eliminating flicker by regulating voltage across the circuit to maintain a steady electric current. This consistency ensures that the current supplied to your LEDs remains stable, effectively mitigating the disruptive effects of AC/DC conversion. However, there are instances where even a constant-current LED driver may struggle to completely eradicate flicker. One common culprit is interference arising from compatibility issues between your control circuitry and LED products. Prior to installation, it's crucial to confirm that your LEDs are compatible with the control circuits and power supply you intend to use. For a flicker-free LED lighting experience, constant current is indeed the name of the game.

"LED Flicker - Understanding the Warning Signals!

If you've noticed a consistent, rhythmic flicker from your LED lights, like clockwork every second, it's essential to heed this warning sign. This regular flicker isn't merely a random glitch; it often indicates a mismatch between your LEDs' power requirements and the capacity of your LED driver. High-quality LED power supplies are intentionally designed to produce this flicker, acting as an alert system. This indicates that your LEDs might be drawing more power than your current driver can handle. To resolve this issue, you may need to invest in a larger, higher-spec power supply or consider using multiple smaller ones for optimal performance.

Aside from power-related concerns, loose wiring and faulty connections can also contribute to LED flickering woes. In cases where multiple electronic devices are clustered together, generating excess heat, this can overload LED dimmers and lead to intermittent flickering. It's essential to address these issues promptly to ensure your LED lighting functions seamlessly. For specialized applications like TV studios and theatres, where high-frequency and high-resolution outputs are necessary, standard LED drivers may fall short. Consider exploring the benefits of constant-voltage LED drivers designed specifically for the film industry. To prevent further flicker-related troubles, it's crucial to identify the root cause of the issue and take appropriate action. So, if you've been wondering why your LED lights are flickering regularly, now you have a clearer understanding of the warning signals they're sending."

Dealing with Dimming

Dimming has become an essential feature in modern LED lighting setups, offering flexibility and mood control. However, it can introduce issues even in a seemingly flawless LED lighting installation. Conventional dimmers employ a technique known as pulse width modulation (PWM), where they extend the 'off' part of each on-off flicker cycle to reduce the overall light output. This method works effectively, as long as the flicker frequency remains imperceptible to the human eye. Some manufacturers are tackling this challenge by developing LED dimmers with significantly faster flicker cycles, aiming for frequencies in the thousands of hertz, similar to the electronic ballasts used in fluorescent lighting. However, there's a catch: higher flicker frequencies require LEDs to be closer to the transformer, which might not always be feasible. Fortunately, you can easily avoid visible flicker caused by PWM by not dimming your LEDs too low. Unlike a few years ago when the minimum dimming threshold was around 50% of full brightness, today's dimmers offer greater flexibility, often allowing you to dim without any visible flicker. Generally, zero-to-10V dimmers tend to be less prone to flicker than mains TRIAC controls."

In this section of our article, we delve into the intricacies of dealing with dimming in LED lighting systems. Dimming can be a double-edged sword, introducing flicker issues even in the best setups. We explore the pulse width modulation (PWM) technique used in conventional dimmers and its effectiveness when the flicker frequency remains imperceptible. Some manufacturers are pushing the boundaries with faster flicker cycles, mirroring the approach of fluorescent lighting ballasts. However, there's a trade-off between flicker frequency and LED proximity to transformers. We also provide practical advice on avoiding visible flicker by not dimming too low, taking advantage of modern dimmers that offer greater flexibility. Throughout, we maintain a concise and reader-friendly approach, ensuring that this information is accessible to all, from beginners to experts in the UK LED lighting scene.


In recent years, LED lighting has emerged as a revolutionary and eco-friendly alternative in the world of illumination. With its numerous advantages, including energy efficiency and longevity, it's no wonder that LEDs have gained immense popularity. However, LED flickering can sometimes mar the experience, and addressing this issue requires a fundamental grasp of the underlying causes. To ensure your LED lighting operates smoothly, remember these essential guidelines:

  1. Choose the Right Power Supply: Always opt for an LED power supply explicitly designed for LED products, avoiding those reliant on mains AC, which can contribute to flicker.

  2. Ensure Compatibility: Make certain that all your LED components, including control circuits and power supplies, are compatible with one another. Mismatched components can lead to flickering issues.

  3. Inspect Wiring and Connections: Regularly check for loose wiring and faulty connections. Ensure that your LED dimmers are not overloaded, as this can also induce flicker.

  4. Consider Constant-Current LED Drivers: Using a constant-current LED driver can help stabilize the electrical flow to your LEDs, reducing the likelihood of flicker.

  5. Experiment with Dimming Levels: When implementing dimming systems, experiment to find the minimum dimming level that should not be surpassed to prevent flickering.

  6. Choose Dimming Systems Wisely: Opt for zero-to-10V or digital volt-dimming systems over TRIAC alternatives for smoother and flicker-free dimming experiences.

By adhering to these guidelines, you can enjoy the full benefits of LED lighting while minimizing the unwanted effects of LED flickering. Keep in mind that a well-informed approach, alongside professional guidance, can go a long way in ensuring your LED lights operate flawlessly, enhancing both energy efficiency and visual comfort.


About Gilbert

Our email: [email protected] Dear readers of Kosoom.uk! I am delighted to introduce myself as Gilbert, your dedicated source of enlightenment when it comes to LED lights. If you have questions about any LED lights, please feel free to contact us to our email: [email protected] We will give you a satisfactory answer as soon as possible. Hailing from the heart of England, I bring to you a wealth of professional expertise and a passion for all things LED. As an Englishman with a fervent interest in illumination technology, I have made it my mission to illuminate the path to understanding LED lights, tailored especially for the inquisitive minds of Britain. With a background steeped in the intricacies of LED technology, I stand ready to shed light on every facet of this brilliant innovation. Through my articles, I intend to guide you through the captivating world of LED lights, providing you with insights that not only unravel the science behind these luminous marvels but also highlight their practical applications and benefits in the UK context. In collaboration with Kosoom, I embark on this journey to demystify LED lights for you. Whether you're curious about the evolution of LED technology, eager to decipher the nuances of LED color temperatures, or seeking advice on optimizing lighting choices for your home, workplace, or public spaces, I am your trusted companion. My articles will offer you clear, concise, and expertly-crafted explanations that bridge the gap between complex technical jargon and approachable, relatable understanding. Stay tuned for a series of articles that will not only elevate your understanding but also brighten up your perspectives on the art and science of lighting.

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