The reasons and how to fix LED lights flickering

It’s hard to mention now when it comes to eco-friendly mobile gadgets that don’t harm human wellbeing and conserve resources. Technology for LEDs. I’m sure most homes are lit by at least one LED light inside / outside of their house. With the extraordinary advantages of this lighting scheme, most countries around the world allow their citizens to make good use of this type of light bulb.

But during use, the product will still have some risks, though not much but also little, to ensure absolute comfort and safety, you need to know the causes and how to fix the LED bulb flicker.

Common LED flashing phenomena

Blinking LED light is an erratic LED phenomenon in which the light energy fluctuates.

For human eyes, who do not adapt in time when there is a change in light is the flicker, flicker of the lamp.

  1. The LED bulb is blinking when turned off: after a period of use, the LEDs often experience flicker when turned on or off. This is a flicker every time the switch is pressed. The light does not always light when turned on, or does not turn off but blinks. If not handled early, the lamp may burn out, resulting in costly repairs.
  2. A flicker of a 1m2 LED bulb is a common phenomenon of people using LED tube lights.
  3. Using poor quality lamps will make the light flicker, not enough to meet the lighting needs.
  4. When it is flickering, the LED tube does not light completely, it may be half-lit, or half-dark. Or sometimes it’s dark when it’s morning.
  5. The LED light blinks continuously: this is a continuous flicker phenomenon, the light suddenly blinks continuously while in normal use.
  6. Flashing is a phenomenon that indicates that your lamp is broken and needs to be repaired or replaced quickly.

Why are the LED lights flickering?

LED bulbs are commonly used for their superior properties, but in the process of using them, if you are not careful, the product will sometimes malfunction when operating. For flashing LED, there are the following causes:

The Driver power supply unit is considered an important part of the LED light. A driver is responsible for converting AC power into direct electricity for good lighting.

Because the lamp source is partially damaged, the power supply is unstable, flickers. The power supply voltage does not match the capacity of the LEDs causing the lamp to flicker.

The power cord inside the lamp is broken

Wires are components that lead the power to the lamp. This is also a common cause of flicker.

When the power cord is cut off, the power supply is unstable or insufficient. This will cause flickering or the lights to stop working.

  • Dimmer compatibility: some existing and even new dimmer switches may not be compatible with LED bulbs. The dimmer also has a different power rating depending on the type of light source whether it’s an LED light, incandescent lamp, etc. This affects the number of lights on the dimmer depending on the specific power.
  • Insufficient power source: each LED has a different capacity, so the power requirement must meet enough power for the lights. The insufficient supply voltage will cause the LEDs to fail quickly, not work stably.

The unstable voltage causes electrical equipment to flicker, leading to the whole system of led lights to flicker continuously. Handling not in time will cause the lamp to burn, to replace the whole system.

The radiator is not working effectively: the radiator in the lamp has the function of radiating heat so that the lamp does not get hot. LEDs that do not dissipate heat well will make the light quickly hot, causing overload and fire. At that time, the lamp begins to experience flicker, which is easy to damage the lamp.

When the lamp has a low IP rating but is installed in a place with high humidity. Steam will penetrate inside, causing electric shock.

LEDs want to use and work well and need a controller with a dimmer switch. This is the type of switch many families are using with incandescent bulbs, halogen bulbs.

The poor quality dimmer will also cause flicker in LEDs. Or the light may be dim, of poor quality.

Quality genuine LEDs usually have life spans ranging from 50,000 hours to 70,000 hours.

However, there are many poor-quality lamp distributors with a life expectancy of only 30,000-40,000 hours.

When the lifespan is nearing the end of its life, the LEDs have two red emitters; glows but flashes continuously.

Some appliances in your home need more electricity when they are turned on for the first time. The starting current of motors in devices lowers the voltage and if the lights are on the same circuit, you may find these lights dim. This is true for many types of lighting including LEDs.

Another common cause of LED flickering is a loose circuit connection. This can be easily corrected. Just rotate the LED bulb tighter to fix the problem. If there is a lot of dust in the device, first clean the connection points to remove dust before returning the bulb.

It could also be due to a loose wire at the connection point. At this point, you should rely on an electrician, who will disconnect the power supply from the device and tighten the wiring to ensure tight and safe.

If there are multiple flashing, dimming lights at the same time, an electrician will check the control panel or junction box to make sure all connections are secured.

The harmful effects of the LED lights flickering

There are two types of strobe with LEDs – visible strobe and invisible strobe. The first type of flicker is visible to our eyes, which is when the light emitted from certain source changes rapidly.

There are health concerns with visible flicker. Short-term exposure to frequencies in the 3Hz to 70Hz range will be associated with epilepsy, with the highest probability of occurring in the 15Hz to 20Hz range. With 1 in 4000 people with photosensitive epilepsy and many others undiagnosed, this has become a no-brainer.

The invisible flicker is the blinking that occurs but we cannot see it. Possible symptoms include dizziness, eye fatigue, headache, migraine, and other general illness symptoms.

When the led light is flashing, the eyes must adjust to being able to catch up with the displayed image. The faster the light flashes, the more eyes have to adjust.

It is like when you wake up in the morning and often get dazzled due to the lack of adaptation to daylight quickly.

When the light changes, the eyes are stimulated by photoreceptors to secrete substances that alert the body. At this point, your eyes will be irritated causing fatigue and soreness.

Flicker may cause negative effects on human health when the lights are on. Affecting the eyes, causing eye fatigue, eye pain, discomfort for humans.

Working under long, flickering light can lead to illnesses like epilepsy; migraine headaches or chronic headaches; decreased vision.

Ability to distract the user while working or decrease motivation. Leading to reduced labor efficiency, adversely affecting businesses.

You can see that when the eyes are exposed to the blinking phenomenon, the eyes will experience pain and fatigue.

This condition will be worse if you experience this phenomenon long term. It is possible to easily suffer from eye diseases such as nearsightedness, farsightedness, and astigmatism, adversely affecting daily activities and activities.

Light is an external factor that greatly affects the morale of the user. When you work in a light space with high stability, your job performance is also very good.

And vice versa, when the light flickers and flickers, it can cause inhibition, not wanting to work, unstable spirit.

Working under long, flickering light can lead to illnesses like epilepsy; migraine headaches or chronic headaches; decreased vision. Ability to distract the user while working or decrease motivation. Leading to reduced labor efficiency, adversely affecting businesses.

Our eyes adapt to the light, making it easy to get dizzy and not see everything. Sometimes it also causes cognitive abnormalities.

You will feel tired, uncomfortable, less efficient at work. Therefore, it is necessary to minimize the phenomenon of working in an environment with flashing LEDs.

Frequently flashing bulbs will cause the lamp life to deteriorate rapidly. Speaking of maximum uptime an LED bulb can last up to 35,000 hours of illumination.

However, if the attached electrical equipment such as starter, ballast, and wire has trouble, it will quickly burn the bulb, black the head of the lamp, and incur unnecessary costs during use.

  • Prolonged LED flickering causes lamp component malfunctions: brightness fades, lights burn.
  • Reducing the life of the LED, costly repairing and replacing components; or replacing the bulb with a new one.
  • In series LED system design, when one LED is flickering, it can lead to flicker or burn out of the other lights.


  • Rapid aging rate, susceptible to disease, making retinal cells faster aging, increasing the risk of macular degeneration. More susceptible to obesity, cancer, and heart disease.
  • The harm of flashing LEDs on the brain: according to Professor Gianluca Tosini, the light from the blue LED is directly related to the biological clock of the brain. More specifically, it primarily inhibits the synthesis of the hormone melatonin, which plays a role in promoting sleep.
  • LEDs flicker due to poor quality: when using poor quality LEDs, of unclear origin. During use, it will cause fire, explosion, debris that can damage the user.

Instructions for fixing flashing LED bulbs

#1. Before you need to check the generalization of the LED bulb again.

  • Check the power supply to the lamp again
  • Check the voltage of the house to make sure the power is stable.
  • If the power source is not suitable for the lamp capacity, it should be fixed soon.

#2. Check the power cord connection in the luminaire

  • Proceed to check the electrical cord connections. If there is a loose connection, the wire should be re-connected.
  • Check that the connector is not exposed, free of dust or moisture.

#3. Check the quality of the Driver power supply

  • After checking the cause of the flashing lights is the driver power supply. The reason is that the driver and the output voltage do not correspond.
  • Replace a new driver with the right voltage to make sure the light works well.
  • Check the steps for installing the Driver power supply unit to minimize any errors that may cause lights to flicker.

#4. Check the radiator’s performance

  • Check the quality of the radiator as the material of aluminum, the structure of the radiator slots.
  • The best aluminum material is from pure aluminum or aluminum alloy for quality heat dissipation.

#5. Install a quality Dimmer switch

  • If the cause is causing the light to blink from the Dimmer switch.
  • Users need to replace the new quality Dimmer switch to control the lamp effectively.

#1. How to fix LED blinking problem #2. The repair steps #1. How to fix LED blinking problem

How to fix LED blinking problem

  • Flicker is not possible with a single red eye. This only happens with an LED with a switch (driver). Flickering can happen if you are using a cheap and poor-quality driver. If possible, try to convert to a good quality driver compatible with a current in (AC) and out (DC).
  • If your home has a dimmer, flicker may occur if you combine them with a dimmable led light. We can only use Dimmable bulbs in a circuit without a dimmer and not vice versa.
  • Check the driver input voltage, and output voltage (from driver to LED), if not compatible, replace it with another driver.
  • The unstable voltage source is also the cause of LEDs flicker. If possible, use a voltage stabilizer and connect the LEDs to a parallel circuit to ensure a steady supply of voltage.
  • The driver converts current from high voltage (110 – 240V) to direct current that the LED can operate. If for some reason, the voltage supplied to the LED is not under the control of the Driver, the LED may switch between protection mode and normal operation mode, causing flicker. In this case, you also need to replace a better driver.
  • A dimmer can turn the LEDs on and off at 0.1ms – 0.9ms cycle to achieve 1 ~ 100% maximum brightness. it usually works at frequencies higher than 200Hz, so flicker cannot be perceived by humans. If somehow it turned on and off at a too low frequency, flicker could be seen. However, this is very unlikely.
  • Finally, your LEDs do not have a waterproof function, maybe they are wet or absorbent. Please check and replace a led light with higher IP protection.

#2. The repair steps

The repair steps are effective when the light is blinking

Step 1: Find the cause of the led light to flicker

When the led light is flashing, it is necessary to check the overall lighting system. From there, find out the reason why the light is blinking such as broken wire, driver,… Make a plan to repair or replace broken components and accessories.

Step 2: Repair the electrical connection or replace damaged components

After having a repair plan, users need to do it as soon as possible. Pay attention to choose genuine new replacement parts, ensure quality, and change accessories by the process, in compliance with electrical safety.

Step 3: Handle the led bulb to turn off and still blink

If after repairing but the light is still blinking. Check the switch on the light to see if the current is properly connected to the wire. After removing the power outlet with the switch, use the electric tester to check the positive lead of the cord connected to the switch; the negative wire has been connected to the led light or not. If it is not correct, change the connection wire to correct the principle.

Methods of protecting the LED from flicker

Correct use will not have the harmful effects of LED bulbs. Not that the higher the wattage of the lamp, the better. Each space will require that the wattage of the bulb is not the same. To choose bulbs with the right capacity, it is necessary to pay attention to the lighting space and the lighting purpose.

  1. LED lamp quality assessment: An objective criterion that customers can consider to evaluate the quality of LED lights is the price and brand of LED lamps. Usually, the cost of the LEDs will be influenced by the quality of the components used.
  2. The LED brand is the second factor that customers can trust because the brand is built on the true experience and reviews from customers. A reputable brand creates quality peace of mind rather than an anonymous brand.

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It’s great that the information we bring will help you in the process of using as well as solving the problem you are having, the LED bulb is blinking. At the same time, knowing about the cause that the LED bulb is flickering will help you to use and know in time to prolong the life of your product.

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