LED light

LED bulb flickering can be traced in almost every instance to a non-compatible dimmer switch in the lighting circuit. Modern dimmer switches create the dimming effect by switching the power supply on and off many times per second. 

Traditional incandescent bulbs have a glowing white-hot piece of metal that creates the light. When the dimmer switches the power on and off, the glowing metal starts to cool down and the net result is the light dims. There’s no flickering.

LED bulbs don’t have glowing filaments. When the dimmer switch goes off and on many times per second, the LED bulb becomes a flickering strobe light. In rare cases, the flickering can be some other power supply issue, which may be the explanation if you don’t have dimmer switches. Contact your utility company in this case.

Some switch manufacturers make dimmer switches that they claim to work well with LED bulbs. It’s a simple project to switch out a dimmer switch, and it might prevent you from having a seizure!

With fluorescent lighting gradually being displaced in favor of LED, many thought the days of dealing with flickering lights were over. Despite flickering being less present in LED than with fluorescent systems, it is certainly still a factor. What are the causes of this, and are there solutions?

Types of Flickering

There are two types of flickering with lights – visible flicker and invisible flicker. Obviously visible flicker is the one our eyes can see, which is when the light output from a given source changes rapidly. It is considered that anything below a frequency of 100Hz can be seen.

There are health concerns with visible flickering. Short-term exposure to frequencies in the 3Hz to 70Hz range are associated with epileptic seizures, with the highest possibility of occurrence being in the 15Hz to 20Hz range. With 1 in 4000 people suffering photosensitive epilepsy and many more who have not been diagnosed, this has become a public safety issue.

Invisible flicker is just as much of a problem if not more. It is the flicker that is present but we cannot see. The symptoms include dizziness, eyestrain, headaches, migraines, impaired thought, and other general sick-feeling symptoms.

Where does flicker come from?

To better understand flickering in lights, consider the theatrical effect known as strobe lighting. This is a deliberate flicker effect that delivers light at certain frequencies, causing the brain to interpret moving objects as if they were in slow motion. These specified frequencies are generally just a few flashes per second, but they are very close to frequencies that cause epileptic seizures.

Unintentional flickering in lighting equipment can be traced back to our power companies that designed electricity flow to use alternating current (AC) as opposed to direct current (DC). With AC power, the sine wave will peak both positively and negatively. This leaves it susceptible to being in a range that will cause flickering, or sometimes an audible hum.

Q: I feel like I’m going to have a seizure. I’ve tried three LED bulbs in my home, and all of them flicker. I’m convinced I’m getting bad bulbs, and the people at the store are being patient. Why are my LED bulbs flickering? Do you think the bulbs are bad, or is it some other sinister problem in my electrical system and my house might catch on fire? –Brad G., Tulsa, Okla.

A. You’d be stunned by the number of people that have the same flickering-light problem. Guess what? It’s almost never the bulb. LED bulbs, for the most part, are very reliable and create consistent, non-flickering light when they get a uniform current flowing through the bulb.

How to solve LED flickering issues?

LED flickering can be tied back to the driver component within the lamp. The essential purpose of the LED driver design is to rely on a simple circuit to control output current, but without altering the frequency, the LED becomes likely to show visible flicker. However, this can be fixed by using constant current drivers, which remove the peaks of the sine wave.

How Dimming Causes LED Flickering

Another challenging variable for LED lamps to avoid flickering is through dimming. Most standard wall dimmers work by phase cutting, which removes part of the sine wave and reduces the voltage. However, this can have negative affects on an LED circuit and actually result in the flicker effect being amplified to a potentially dangerous level (3-15Hz range).

This is one of the main reasons why it’s hard to trust old dimming systems with new LED bulbs. The only way to be sure no flickering will be present is to get LED-specific dimming solutions for your LED lamps. It all comes back to the fact that LED is a long-term investment. In turn it is worth doing research to ensure you are getting a quality LED bulb, and that if you plan to dim with it you are getting an LED dimming system that has been tested as being compatible to the LED bulbs you intend to use.

How To Fix Flickering LED Lights

Investing into LED lights is a great way to save money, but sometimes those lights can cause a few problems. They are expensive to replace every time they flicker and those lights can flicker a lot! The good news is that this issue can often be fixed. Don’t run out to buy a bunch of bulbs because there’s a good chance they’ll all flicker. Take a look at these issues instead to eliminate the flicker once and for all.

Check the Amount of Current In Your Home

The most common reason why LED lights will flicker, especially if it is only an occasional problem, is because there are voltage changes happening within the wiring of the home. This is because there is a current flow in the wiring and the resistance of each wire uses some of the voltage. If you turn on a washing machine while the refrigerator is running and this is when you see a flickering LED light, then there’s a good chance you have loads turning on and off that change the voltage levels and this is causing the flicker.

Why Do My Motion Sensor Lights Keep Flashing On and Off?

Your motion sensor lights are supposed to give you a sense of security and peace of mind.

Instead, they’re driving you crazy because they won’t stop turning on and off, regardless of whether there’s an actual intruder setting them off or not.

If your motion sensor lights keep flashing on and off, you should try:

Checking whether they’re actually flashing on and off or just flickering

Adjusting the motion sensor positioning and settings

Adding “side blinders” to your sensor

Let’s take a closer look at some of the ways you can stop false alarms from your motion detector lights. 

If you’re not up for any DIY troubleshooting, just contact us and we’ll send over one of our electricians to find and correct the problem.

First off, are they flashing on and off or just “flickering”?

If the problem is that your motion sensor lights are flickering, you have a completely different problem than the one we’re addressing in this article.

Flickering lights (lights that produce unsteady, rapid changes in brightness) are usually caused by one of 3 things:

A bad bulb

Bad connection between the bulb and the light fixture

Problems within the circuit 

See “Why Do The Lights In My Home Keep Flickering?” for more help on this problem.

So if you have a motion sensor light that flickers when it’s on, we suggest you first try changing out the bulb. If this doesn’t fix the problem you’ll want to have an electrician check the circuit for bigger problems.

However, if the problem is that your motion sensor lights are false-triggering, continue reading below for some troubleshooting tips.

I have recently been having a fault with my LED flood light in my garden. It works OK for about 3 minutes and then flickers like a strobe. If you turn it off for a period, then turn it back on again it works for 3 minutes again and then again flickers like a strobe. I have had these lights for about a year and only used them a handful of times so am dissapointed this has happened. I have attached some images of the light and its manufactuer label. Can I fix this myself? Is it the chip or a capcitor or something inside?

I was wondering if someone could tell me if these ones are any good because they were chosen by the electrician who installed the wiring and what manufacurer people reccomend I go for? I was shocked to see you can buy 50 watt floods LED for ~£20 (what are you going to get for that money) and thought they may go wrong as most likely cheap foreign rubbish chips etc.

The magazine I am looking at (CPC) has choices from Razorlux. Price is not so much of an issue if they work for a decent time 50000 hours, but replacing cheap lights every year for 20 pounds a pop adds up.


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