Flicker in LED light refers to the rapid and repeated fluctuations in light output or brightness that can occur when LEDs are not driven by a stable and continuous current. The flickering effect is usually not visible to the naked eye because it happens at a high frequency (usually thousands of times per second), which is beyond human perception. However, the flicker can still have various effects on human health, visual comfort, and the performance of electronic devices.
Flicker in LED light can be categorized into two types:
Visible Flicker: While most LED light flickers at a high frequency that is not visible to humans, some LEDs may exhibit visible flickering, especially when operated at low frequencies. This can be bothersome and uncomfortable for users, leading to eyestrain, headaches, and fatigue.
Non-Visible Flicker: Even though the flicker is not visible, it can still affect human health and well-being. Non-visible flicker has been linked to various issues, including triggering migraines or worsening the symptoms of individuals with light-sensitive conditions.
Flicker in LED light can be caused by several factors, including:
PWM Dimming: Many LED lights use Pulse Width Modulation (PWM) dimming to control brightness. At low dimming levels, PWM dimming can lead to visible flicker.
Poor Driver Design: Inexpensive or low-quality LED drivers may not provide stable current, resulting in flickering.
Incompatible Controls: Some LED lights may flicker when used with certain dimmer switches or lighting controls that are not designed for LED compatibility.
Mains Voltage Fluctuations: Variations in the mains voltage can lead to fluctuations in LED light output.
To mitigate flicker and its potential negative effects, it’s essential to use high-quality LED drivers and lighting controls designed for LED compatibility. Manufacturers are also becoming more aware of the importance of reducing flicker in LED lighting products and are producing LEDs with improved driver designs and dimming capabilities.
When selecting LED lighting for critical applications, such as workplaces, schools, and healthcare facilities, it is advisable to look for LEDs with minimal flicker and to consider those that comply with international standards for flicker reduction, such as IEC 61000-3-3. Additionally, users experiencing discomfort from visible flicker should choose LED lighting products with PWM dimming systems that operate at higher frequencies (above 1 kHz) or consider using non-dimmable LED solutions.