AC LED are special LED modules that do not require a specialized power supply. Thanks to this aspect we may feel LED modules in AC really “Green” because the power supply in DC LED modules is definitely not only a complex and expensive part to manufacture but also problematic due to the need to dispose it at the end of life.
In AC modules, LEDs are directly connected to the mains via a bridge rectifier without an isolation transformer and then regulated by electronic circuits. The lack of the isolation transformer implies the presence of phase on some points of the circuit so that you must be extremely careful in using them and protecting the user from accidental contact. Additionally, each lighting fixture assembled with this kind of LED should be fully tested in terms of electrical safety.
EDISON’s bright performance on this type of circuit, has come to the threshold of 110lm/W for 6000° K, with color rendering indexes reaching nearly 90 also for devices declared CRI > 80. The R9 is always greater than zero almost touching the value of 30. The colour consistency SDCM (Standard Deviation of Colour Matching) is 3-step MacAdam, as in the best tradition of Edison LEDs.
Electrically, the power factor is very good and always greater than 0.9 with a fundamental current harmonic distortion never touching 15% for the >15W dimmable versions. IEC 61000-4-5 surge resistance ranges from 500 to 1000V depending on model. Radio interference level (EMI) is basically harmless because applications do not present high frequency switching electronic devices on board.
The power ranges from 5 to 25W with streams from 500 to 2500 lm, in dimmable or not versions. In versions offering adjustable intensity, this can be done by an external TRIAC or IGBT dimmer.
The nominal frequency of these devices that is 50Hz, which becomes 100Hz once the mains voltage is rectified, does not make them immune from flicker that we can try to maintain at low levels with specific switch on sequences of LEDs.
Needless to say, the absence of the cumbersome power supply makes these devices easily fittable into appliances with minimalist design and very convenient to use.