Advantages and Disadvantages of Triac Dimming

Disadvantages of Triac dimming

1.The Triac destroys the waveform of the sine wave, thereby reducing the power factor value, usually PF is less than 0.5, and the smaller the conduction angle, the worse the power factor (only 0.25 at 1/4 brightness).

2.Similarly, non-sinusoidal waveforms increase the harmonic coefficient.

3. Non-sinusoidal waveforms will generate serious interference signals (EMI) on the line

4. It is easy to be unstable at low load, so a bleeder resistor must be added. This bleeder resistor consumes at least 1-2 watts of power.

5. When the ordinary Triac dimming circuit outputs to the LED driver power supply, there will be unexpected problems. That is, the LC filter at the input end will cause the Triac to oscillate. This oscillation is irrelevant to incandescent lamps, because the thermal inertia of incandescent lamps makes the human eye unable to see this oscillation. However, it will generate audio noise and flicker for the LED drive power supply.

Advantages of Triac dimming

Although Triac dimming has so many disadvantages and problems, it has certain advantages, that is, it has formed an alliance with incandescent lamps and halogen lamps and occupied a large dimming market. If LED wants to replace the position of Triac dimming incandescent lamps and halogen lamps, it must also be compatible with Triac dimming.

Specifically, in some places where Triac dimming incandescent lamps or halogen lamps have been installed, Triac dimming switches and knobs have been installed on the wall, and two connecting wires leading to the lamps have been installed in the wall. It is not so easy to replace the Triac switch on the wall and to increase the number of connecting wires. The simplest way is to do nothing. Just unscrew the incandescent lamp on the lamp head and replace it with an LED bulb with a compatible Triac dimming function. This strategy is like LED fluorescent lamps. It is best to make it exactly the same size as the current T10 and T8 fluorescent lamps. No professional electricians are required. Ordinary people can directly replace it, and it can be popularized quickly. Therefore, many foreign manufacturers of LED driver ICs have developed ICs that are compatible with existing Triac dimming.

That is, it is easy to install and does not require additional wiring.