LEDs powered by Alternating Current (AC) will switch on and off rapidly, which is known as the AC frequency or cycle rate. The cycle rate is typically high enough that the human eye cannot perceive the on-off switching, and the LED appears to be continuously illuminated.
In traditional bulbs, the filament glows continuously, even between flickers, which is why the flicker is not noticeable to the human eye. However, this results in a significant amount of energy being wasted in the form of heat, reducing traditional bulbs’ energy efficiency. On the other hand, LEDs do not use filaments and do not emit heat like traditional bulbs. Instead, LEDs use semiconductors to emit light, which makes them more energy-efficient. The on-off switching of the LED can be noticeable if there are issues with the power supply or driver, but under normal conditions, the switching happens rapidly enough that the human eye cannot detect it.
If the on/off cycle of the input AC is disturbed, it can result in fluctuations or flickering of the LED output light. The on/off process of the AC power supply needs to be consistent and stable to ensure that the LED operates smoothly and without flicker. If the cycle is disrupted, it can cause the LED to flicker or fluctuate, which can be noticeable and distracting. In addition, if the power supply frequency is less than 50 Hz, it can result in fluctuations or flickering of the LED output light. In some countries, the power supply frequency is 60 Hz, which can also cause flickering if it is inconsistent. For example, the human eye can detect flicker at frequencies lower than 50 Hz.
In general, when LED lights flicker, it is usually not a result of a defective LED bulb but rather the power supply feeding it. With modern LED installations, the LED is no longer powered by the main AC supply but instead by a driver that converts AC power into DC power. The driver typically steps down the main electricity supply to a lower voltage DC that is more suitable for use by the LED. This helps to ensure that the LED receives a steady and reliable power supply, which reduces the likelihood of flickering or other issues.
A constant current driver will regulate a continuous current in your LED circuit by varying voltage, reducing flickering to a great extent. But then again, if your LED bulb is incompatible with such a driver, it won’t work! In many cases, the power supply is causing problems, so check if your LED driver is working well or if your LED driver is compatible with the LED.
- Use High Frequency (HF) Driver
To mitigate the problem of flickering in LED lights when they are dimmed, manufacturers are currently developing more sophisticated dimmers that utilize high-frequency cycles. Increasing the frequency makes the human eye less likely to perceive flickering, even when the LED light is dimmed.
Installing high-frequency (HF) drivers can significantly reduce the time interval between LED lights on/off cycles. This helps to reduce the amount of flickering observed, resulting in a more stable and consistent light output.
- Use Constant Current Driver
Using constant current drivers is an effective solution to minimize flickering in led lights. These drivers adjust the voltage to produce a steady and uninterrupted current, ensuring the LED receives a constant power supply with minimal disturbance. The flickering can be significantly reduced by reducing the effect of AC to DC conversion.
When your LEDs are connected to a capacitor that controls the current going into the bulbs, a faulty capacitor can change the “equivalent series resistance” (ESR). This can cause power losses, heat buildup, instability, and reduced efficiency. Another factor contributing to flickering in LED lights is the “relaxation oscillator” inside the capacitor, which can cause it to oscillate between on/off states. This results in nanosecond-long illuminations when the light is turned off, which can create flickers in the LED light.
A capacitor that is not functioning correctly can be a common cause of flickering in LED lights. When the ESR of the capacitor changes, the power losses can lead to heat buildup, which can further contribute to the instability and inefficiency of the LED light. Additionally, the relaxation oscillator inside the capacitor can result in rapid on/off cycles, creating flickering in the LED light.