LED flicker – where does it come from?
People react to light – we have known that for a long time! The day-night rhythm, hormonal fluctuations, even psychological effects are known and proven. So if natural light already has such serious effects on us and our bodies, what happens with artificial light, especially with “poor” artificial lighting?
Do you know it? Headache, mild nausea or dizziness? There are many reasons for this, one of them can be the wrong LED lighting! And not only on the PC monitor, mobile phone or TV, but on cheap and bad LED lamps. They flicker – and this LED flicker has long-term effects on us. This phenomenon can go as far as the visible stroboscopic effect, which we know from discos. In most cases we do not even notice the flickering and that is the problem!
BUT WHERE DOES THE LED FLICKER COME FROM?
In principle, it is quite simple to explain: Our current from the line is alternating current, which means that at very, very short intervals the voltage changes its polarity from PLUS to MINUS and vice versa. To be exact 50 times a second, that is the frequency of 50Hz. Exactly this alternating voltage is optically reproduced by the LED illuminant. And this always with double the frequency, the LED goes on and off 100 times a second. Always to the positive and negative half-wave on and around the zero point off. Actually, LED lamps would need direct current to work ideally and to shine without any flickering.
A ballast electronics in the LED illuminant (hidden in the base) converts the alternating current from the line into direct current, or modulates the frequency so that it is no longer perceptible.
A high quality electronic circuit can reduce the flicker of dimmable LED lamps to nearly 0. However, this involves a material effort and therefore costs. Therefore, we can assume that in most cheap products no or only insufficient ballast electronics are installed.
Many non-dimmable LED illuminants do not have the problem of flicker because they are based on another, simpler technology that produces a constant voltage. Nevertheless there is a lot of flickering even in the non-dimmable range, e.g. many G9 and R7s in glass housings and LED lamps with driverless AC direct technology.
HOW DO I FIND OUT IF MY LED LIGHT IS FLICKERING?
There is a very simple test that anyone can perform at home without any major aids, the so-called camera test. In our latitudes with a mains voltage of 50Hz and a normal camera or mobile phone (24fps) you can detect the most common 100Hz flicker.
IT WORKS LIKE THIS:
Switch on LED illuminant and camera (start camera APP on the mobile phone). Hold the camera or mobile phone very close to the LED. DO NOT take a photo or video, just watch! If the lamp flickers, dark bars run over the picture / monitor. The darker these bars, the worse the flickering is!
WHAT TO DO ABOUT THE LED FLICKER?
In recent years, the flicker problem has increased and has come more and more in o the focus of LED users due to the widespread switch to LEDs and the banning of old incandescent lamps. Especially the above mentioned driverless AC direct technology and also G9 and R7s LED in glass housing are very cheap to produce and flood the market. There are some, especially relatively complex measurement procedures and methods to measure the “flicker level” of LED lamps. None of them takes all factors into account and is 100% meaningful. And they are hardly understandable for the normal end user!
The reference and starting point for retrofit LED illuminants is the incandescent lamp. Because, what hardly anyone knows: this also flickers, but to a very small extent. From experience and habit we know that flickering is not perceptible in this area and above all is not harmful.
If you want to learn more about the exact measurement methods, get an overview of measurement results and above all get to know a new and very sophisticated approach, you can get detailed information here at “Der Lichtpeter”.
HELP WITH LED FLICKER PROBLEM
Unfortunately, there is no valid law yet that requires the manufacturer or supplier to specify the flicker degree of their products. Only the manufacturer knows what he is using and installing! As customers we have a hard time to find out if the LED lamps we buy are within the tolerance range or not.
At the end of 2019 a new EU regulation “EU2019/2020” was published, which will be effective from September 2021. It stipulates that the limit values for the flicker measured as PstLM ≤1,0 and Storboscope Effect (100Hz flicker) measured as SVM ≤0,4 are required.
SEGULA LED – WHAT WE DO
SEGULA’s promise to our customers: We use only the highest quality and most modern ballast electronics for our dimmable LED lamps. For our measurements we use the values prescribed by the EU. By the way, since the publication of the directive, some other manufacturers have also been doing this. To make it easier for our customers to understand, we mark our LED illuminants with the value SVM, which is the easiest to orientate yourself by! On request we have of course all values available, which are interesting for the topic flicker!
When buying, look out for our new symbol. You will find it in future on packaging and in the technical data of our dimmable LED lamps!