Digital Dimmings (1) DSI and DALI Control Nevertheless, in order to be capable with a PWM dimmer, the power supply should be able to run the LED at a high enough frequency, and this will greatly increase the technical requirement of an LED driver. This suitable for LEDs that need to maintain colour consistency when dimmed down to lower than 40%, and lighting applications with mixed colour control. It switches the input current of the LED lamp at a high frequency between 0A and the rated current, and this modification of on-off rate of LED will result as the change of output percentage. Instead of adjusting the DC current, PWM dimming achieve the same effect by varying the duty cycle of the constant current.
In a technical perspective, PWM dimming can be categorised as a type of Digital dimming. Moreover, for a 0-10V dimming system, each control channel requires one wire, and the excessive amount of cabling can cause a considerable voltage drop that lowered the energy efficiency. However, in many cases, the light can only be dimmed down to 10% due to the limitation of the power supply, and a switch or relay is needed to completely turn the light off. Theoretically, the LED will have 100% output when the dimmer is scaled at 10V while the dimmer is at 0V, the LED will have 0% output, or be turned “OFF”. This 0-10V dimmer is connected to the circuit in parallel, and dims LED simply by adjusting the input to the lamp via scaling the DC voltage at the dimmer side. Nowadays, some of the LED fixture is also designed for this dimming methodology due to its simplicity. 0-10V analogue:Īs one of the earliest and simplest lighting control, 0-10V analogue dimming is used for early fluorescent dimming and still being used today. So when you choosing a dimmable LED, it is better to clarify the capable dimming method for the product before getting a dimmer for it, or you can use a “Universal” dimmer, as it is suitable for both leading edge and trailing edge dimming. However, because LED retrofits are mostly for the existing incandescent or halogen fixtures, which makes many manufacturers designed their LED lamps to be suitable for leading edge dimmer. Summary for phase-cut dimmingĪfter comparing these two Phase-cut dimming methodologies, it is clear that for most LED lamps, trailing edge dimming is a better option comparing to leading edge dimming. In comparison to leading edge dimming, it will not exert high inrush current, while not causing buzzing sound when dimmed.
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It can be used for electronic driver and low voltage transformers. This is also called “electronic dimming”, which can be considered as a reverse form of leading edge dimming, as it turns of the end of the AC input waveform. Nevertheless, it can cause buzzing noise when dimmed, and when it is used for an LED lamp, it can produce a high inrush current to its electronic component, and eventually the entire luminaire will be damaged. It fits the traditional incandescent lamps or magnetic low voltage transformer. It turns off the sinusoidal signal of the electrical current at the front of the AC input.
This can be alternatively called as “TRIAC dimming” or “incandescent dimming”. There are mainly four types of phase-cut dimming methods: a. This method dims the output illuminance through cutting the phase of the AC current, which will decrease the power input to the light. In general, there are mainly 4 protocols that are using in Australia: 1. When facing this massive amount of options, consumers are frequently encounter such question: Which dimmable LED should I choose? How LED lights be dimmed?īefore answering this question, it is necessary to clarify that most of LED lamps are powered by electronic drivers, as they are more suitable for DC device. However, as people may know, there are a huge amount of different dimmable LEDs in the Australian market, and the dimming methodology for all these products are varied. The rising cost of electricity is certainly driving consumers, retailers and business owners to seek for energy-efficient lighting technologies, and dimmable LED is considered as one of the most efficient choices.
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