LED drivers provide a reactive load to the dimmer. Put simply, the ratio of voltage to current is not a direct proportional ratio. The higher power is, the higher holding up current is in general.Īlthough Triac dimming has the positive aspects of uncomplicated control and simple installation, the voltage waveform of the power supply may be situated at a distortion status to give rise to the problems of a low PF and an elevated harmonic voltage. For forward-phase Triac dimmer, there is minimum amount of holding up current and it is connected with the power level of the dimmer. On the contrary, a reverse-phase dimmer cuts out a portion of the AC waveform at the trailing edge in order that the dimmer turns off part-way through the sine wave. A forward-phase triac dimmer cuts out a portion of the AC waveform at the leading edge of each half sine wave. This is what's called phase dimming since it is often convenient to specify the position of the missing voltage with regards to a fraction of the period of the AC input voltage measured in degrees. A Triac circuit operates by delaying the beginning of each half-cycle of alternating current (ac) power, which is referred to as 'phase control.' By making use of the Triac phase-controlled operating principle, the supply voltage of the lamp circuit is regulated by controlling the conduction angle of the Triac element to chop out a part of the sine wave voltage input from the AC power network, to reduce the average value of the output voltage, as a way to realize the dimming function for LEDs. A Triac (Triode for Alternating Current) is a bidirectional thyristor device for alternating current which may be regarded as a switch that is able to conduct current in either direction. The first is forward-phase dimmer (Triac dimmer) and the second is reverse-phase dimmer (Transistor dimmer). In offline LED dimming application, there are two forms of most popular dimmers available in the market. There are various varieties of dimming technologies for lighting applications.

Do you need a led dimmer for led lights