LED lighting is becoming the new design standard for its efficiency and longevity. But hand in hand with these more efficient lamps are lighting controls such as dimming. While dimming has been around for decades, it continues to grow in popularity. While it still provides ambience for a space, architects and building owners are now discovering the energy benefits of dimming. Finding a dimming driver that can smoothly transition between lighting levels is critical to achieve this. Silicon-controlled Rectifier dimming, or SCR, has been a popular method of dimming for decades due to its stability. Also known as an autotransformer dimmer, this device has been used with incandescent lights for years to provide consistent and inexpensive dimming solutions. Now that LED lights have gained popularity for their efficiency, drivers must adapt to provide the same level of reliability using new methods. Even with this challenge, there are great solutions. Lighting professional have found that using SCR dimmable LED power supplies to be one of the best and most efficient ways to provide consistent dimming.
This common method of dimming uses a silicon device called a thyristor to turn the waveform on halfway through its cycle, which allows for power delivered to a lamp to be varied. This method was developed in the 1970s and has been the most commonly used dimming technology for decades. It accomplishes this by varying the point at which the waveform turns on which alters the amount of current or power that goes to the lamp. This is the simplest and cheapest method of dimming. One drawback of SCR dimming is the hum, or singing, sound it makes when the voltage drops. However, this is and has been eliminated with a choke fitted to the dimmer module. The choke can reduce the rate at which the current increases, thus eliminating the sound.
Dimming has now become a method to reduce electricity because modern dimmer drivers such as those that use SCR can now cut the supply of current on and off at rapid speeds. This method interrupts the current during an alternating current (AC) half-cycle. This allows you to achieve the dimming effect of a design while maintaining an efficient lighting system. Using dimmers also prolongs the life of light bulbs. By reducing the amount of power to bulb, it experiences less stress and heat. LEDs benefit from this because the dimming range is broader. LEDs can turn down to less than one percent of full output compared to compact fluorescent lights that can only reach 10 to 30 percent. With an LED lighting system, you can achieve the desired aesthetic while also maintaining lower energy bills and a system with an extended lifespan.
While LED dimming may be advantageous, choosing the right power supply is the key factor in improved efficiency and overall operation of a lighting system. SCR has the advantage of being a well proven method of dimming for decades, but the technology requires some tweaking to adapt from the standard incandescent lamp technology to LED. For this reason, it’s important to consider the applications best suited for SCRs. Because of their singular forward-voltage only they are best suited for medium to high voltage applications such as lamp dimming, power regulators and motor control. However, some of the more sophisticated products on the market such as GRE’s UL/cUL Listed Class 2 Linear Lighting Pro Constant Voltage LED driver can compensate for the lower voltage ranges and forward phase types such as SCR.
SCR dimming drivers are a widely used, reliable, and inexpensive method of dimming technology. But to marry them seamlessly to new LED technology, it is necessary to consider the application. Choosing a driver module that can also overcome flickering or inconsistencies at low voltages should also be considered. A TRIAC dimmable LED driver delivers a wide and constant dimming range that is free of flicker with best-in-class dimming performance, and high efficiency. Supporting products include the constant current XLA with flying leads. The unit has wide dimmer compatibility and supports most phase type dimmers in the market, including leading edge and trailing edge, electronic low voltage (ELV), TRIAC, and SCR dimmers. When chosen carefully, though, SCR drivers can be paired successfully with LED lighting systems to provide not only superior, efficient lighting schemes, but also the most reliable, simple, and cost-effective solution.
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