Everything you need to know About Triac Dimming for LEDs


LED light fixtures have become ubiquitous worldwide due to their energy-saving capabilities. However, when it comes to color depiction and dimming, LEDs still lag behind traditional incandescent bulbs. In residential settings where incandescent bulbs are still used, compact fluorescent bulbs, LEDs, and halogen lamps are being replaced by dimmers with integrated thyristor circuits known as TRIACs. TRIACs are commonly used in these systems due to their ability to control high-power devices reliably and efficiently.

What Exactly is a Triac?

A TRIAC is an electronic component with three terminals capable of conducting current in both directions when activated. It is equivalent to two silicon-controlled rectifiers (SCRs) with their gates wired in reverse parallel and connected to each other. By applying a gate signal similar to an SCR, a TRIAC can accept current in either direction. TRIACs were developed to facilitate the management of AC power. They come in various packaging options, are safe to use with different voltages and currents, and are suitable for a wide range of applications.

How Does Triac Dimming Work?

Triac dimming involves gradually reducing the input voltage until the TRIAC dimmer is triggered, resulting in a drop in output voltage. This process changes the effective value of the AC, allowing for dimming. The first step is altering the angle of conduction for each AC half-wave. TRIAC dimming controllers function as quick switches, regulating the current flowing through an LED lamp. When the device is powered on, it begins to move electrons through its internal components by interrupting the voltage waveform, reducing the flow of electricity, and subsequently reducing the bulb’s brightness. The speed at which the switch responds determines the amount of energy released and affects the bulb’s lifespan.

Why Choose TRIAC?

TRIACs are widely used in electrical control systems and are suitable for powering small motors and fans. They offer flexibility, precise control, high efficiency, and ease of operation, making them a preferred choice for manufacturers. TRIACs are compatible with various LED light fittings and bulbs, making them an ideal option for dimming LED lights.

Different Types of Dimming

Dimming drivers for LEDs can be categorized into Triac dimmers, LED dimmers with a voltage range of 0-10 V, and pulse width modulation (PWM) dimmers. Each method adjusts the current, voltage, and frequency output to achieve the desired amount of light.

  • Triac Dimming: Triac dimming is a physical process commonly used for incandescent, compact fluorescent, and LED bulbs. It involves altering the AC waveform’s conduction angle to reduce the output voltage effectively, thereby dimming the light.
  • PWM Dimming: Pulse-width modulation (PWM) is a digital control method that uses the output of a microprocessor to switch analog equipment on and off at regular intervals. It offers precise control over the intensity of an analog signal, reducing energy consumption.
  • LED 0/1-10V Dimming: This analog dimming method utilizes a driver with additional +10V and -10V ports to control the current output. Dimming is achieved by adjusting the voltage, with 0V representing pitch black and 10V indicating maximum brightness.
  • Dali Dimming: DALI dimming involves wiring control cables with two cores, allowing for digital rewiring of lighting circuits while maintaining pre-set parameters. DALI lighting provides comprehensive dimming control for various types of LED lights, including RGBW and Tunable White lighting.

Advantages and Disadvantages of TRIAC Dimmers in LEDs

TRIAC dimming offers several advantages, including high efficiency, precise control, compact size, lightweight construction, and ease of operation. It is a popular dimming method and generally compatible with LED lighting. However, TRIAC dimmers have a limited dimming range, and even at their minimum setting, a small amount of current may still flow through the switch. This can pose challenges for LED dimming, but with proper installation and compatibility checks, TRIAC dimmers can effectively control LED lights.


Understanding Triac dimming is essential for harnessing the full potential of LED lighting. With TRIAC dimmers, LEDs can achieve the desired level of brightness, providing energy-efficient and versatile lighting solutions for various applications. When selecting and installing TRIAC dimmers, it is crucial to ensure compatibility with LED lights and follow proper wiring procedures. By harnessing the benefits of TRIAC dimming, you can optimize the performance and longevity of your LED lighting setup.


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