How to choose a Flicker-Free LED strip Lighting?

LEDs and Flicker

If you've ever noticed the lights flickering, chances are it's due to fluctuations in power. Flicker effect, "ripple" to more obvious strobing. Light flicker isn't just annoying, it can have a significant impact on workers' well being, students'concentration levels, patients' recovery times and generally reduce the performance of a lighting system. So what can you do to ensure flicker-free LED lighting in your home or workplace?There are two types of flickering with lights: visible flicker and invisible flicker.

Visible flicker (considered anything below a frequency of 100Hz) is observable by the human eye and is typically undesirable except in special applications such as stroboscopic lighting. Invisible flicker is flickering that is present but not perceived by the naked eye. If left uncontrolled, lighting flicker can cause an abundance of biological and health issues that can ruin an otherwise well-designed space. Neurological problems (including epileptic seizures), dizziness, headaches, fatigue, increased autistic behavior (especially in children), eyestrain, impaired thought, and migraines are some potential flicker-induced impairments.

Many LED bulbs will flicker at 100-120 Hz (2x line frequency), at which even 10% flicker can have detrimental effects. At higher frequencies, higher flicker percentages are acceptable. 

What Causes Flicker?

Because LEDs have no persistence, the light output frequency will correlate with the output waveform of the power source or driver. voltage delivered to a source fluctuates between on and off . A source without quality electronic circuitry – such as a ballast, driver, or capacitor — will flicker.
 AC-LEDs,the simpler circuit design , lack of a driver, and consequently, AC-LEDs can produce up to 40% flicker at full output. At dimmed levels, the flicker percentage can be even higher. Trusted advice is key to find the right balance between cost and performance and most importantly, ensuring the best quality of light for any installation.

Another cause for flicker is with dimming and control circuitry that uses a method called PWM (pulse width modulation), a common dimming technique. Since this method simply moderates the power input to the LED, light flicker will be highly evident unless the PWM frequency is also regulated.PWM cycles the LED from the maximum current to zero current, essentially switching the current on and off very fast, and repeats this process at a fixed rate. Dimming is controlled by the driver, so choosing the proper driver is crucial to getting the desired lighting effect. Drivers that use PWM at a low enough frequency have a high potential to introduce undesirable flicker.

How to Reduce LED Flicker

One way to achieve flicker-free LED Strip Lighting is to add a capacitor to the driver output that buffers the output ripple. Unfortunately, this potentially reduces the lifespan and reliability of the system, if low-quality capacitors are used.

For example.rfer to CIY LED 230VAC flicker-free triac dimmable LED strip,it add capacitor.

Another method is to use drivers with a two-stage power factor correction (PFC), which will modulate the output frequency, ripple and noise.In either case, it is crucial to select a good quality LED driver that minimises fluctuations in the output ripple current, so that you can be sure to avoid undesirable effects. Lighting designers should work with LED Driver manufacturers and suppliers to identify a solution that is compatible with all aspects of the luminaire design, insulation and/or application considered.

Capacitors are typically used in LED drivers to smooth and reduce the ripple that comes from the power supply. Selecting a quality capacitor for an LED lighting system can help to avoid flicker, eliminate excessive heat, and ensure the longevity of the LED lights. Even lamps with capacitors may flicker; it is a matter of the quality of the lamps and their components. Lower cost lights/lamps have lower quality capacitors.

It is also important to verify that the LED lighting product is compatible with the dimmers or other control circuits used in the lighting system. A faulty photosensor or timer can cause flicker issues. Moreover, random flickering may be an indication of another problem in the lighting system, such as loose wiring and interconnections. The quality of the electrical supply can also result in problems with power fluctuations.