1. Power Factor (PF)

Power Factor (PF) describes the efficiency of power usage in an electrical system. It measures the phase relationship between voltage and current, reflecting how effectively electrical power is being used.
A low power factor causes multiple issues:
1. Increased reactive power, leading to energy waste;
2. Higher current in AC circuits, which results in heat buildup, increased losses, and requires thicker cables and larger transformers;
3. Voltage instability and harmonic distortion, which can disrupt both the power grid and other connected equipment.
In many regions, especially for high-power applications, utility companies require equipment to meet a minimum PF standard. Devices with low PF often need additional correction equipment to bring them into compliance.
We strongly recommend choosing LED luminaires with high PF drivers, especially in installations with a large number of fixtures—factories, shopping centers, hotels, office buildings, hospitals, etc. In such scenarios, a power factor of PF > 0.9 is typically required. For residential use, the requirement may be slightly relaxed.
Today, the cost difference between low-PF and high-PF LED drivers is negligible, so it’s advisable to choose PF > 0.9 by default. At LEDTEK, we exclusively use high-quality, high-PF LED drivers from brands such as Meanwell and Lifud to ensure product reliability.

2. Total Harmonic Distortion (THD)

Total Harmonic Distortion (THD) quantifies the distortion of current or voltage waveforms caused by harmonics—frequencies other than the fundamental 50Hz or 60Hz.
LED drivers are typically based on switching power supply topology, incorporating inductors, capacitors, and transformers. These components draw current in pulses rather than smoothly, which distorts the sinusoidal waveform of the AC supply. The resulting high-frequency harmonics feed back into the power grid, polluting the supply network.
High THD levels can cause serious issues:
• In three-phase four-wire systems, a balanced load ideally results in near-zero current in the neutral line. However, large-scale use of high-THD LED luminaires causes significant harmonic current accumulation in the neutral conductor, leading to overheating, tripping of breakers, or even fire hazards.
• These problems are often not apparent during manufacturer aging tests, but become critical in real-world installations, particularly in large-scale commercial or industrial projects.
To avoid such risks, select LED luminaires with low THD, ideally THD < 20%, with THD < 15% being a desirable standard. At LEDTEK, we use only low-THD LED drivers from reputable brands such as Meanwell and Lifud, ensuring safe and clean power performance.

3. Ta and Tc (Temperature Ratings)

Two temperature ratings frequently appear in LED driver datasheets:
• Ta (Ambient Temperature): the surrounding air temperature in which the device operates;
• Tc (Case Temperature): the maximum temperature measured at a specific point on the driver’s casing.

🔹 Ta (Ambient Temperature)
This parameter defines the operating temperature range of the luminaire. For example, Ta: -20°C ~ +45°C means the LED driver can reliably function within that environment. Inappropriate Ta ratings can result in failure to start in cold conditions or overheating in hot environments.

🔹 Tc (Case Temperature)
This is a critical safety and performance limit. It is usually indicated on the product casing with a “Tc point” for accurate measurement. For example, Tc max = 85°C. The higher the allowable Tc, the more thermally robust the driver.
In general:

• Indoor commercial LED luminaires (such as LED Downlight, LED Panel light, LED Linear Light) tend to have lower Ta and Tc ratings;

• Outdoor or industrial luminaires (e.g., street lights, flood lights, high bays) must support wider temperature ranges and higher Tc limits due to harsher conditions.

Other Electrical Parameters

Other electrical specifications such as input voltage (e.g., AC 110–240V 50/60Hz), output voltage, output current, and output power are usually straightforward and widely understood, so we won’t elaborate on those here.

Conclusion: Choose LED Luminaires Wisely

When evaluating the electrical performance of an LED luminaire, focus on the following:
• ✅ High Power Factor (PF > 0.9)
• ✅ Low Total Harmonic Distortion (THD < 15–20%)
• ✅ Appropriate Ta and Tc ratings for your specific installation environment
These parameters help prevent common electrical issues, reduce long-term maintenance costs, and improve system safety.
For maximum reliability, choose luminaires that use power supplies from well-established brands such as Meanwell, Lifud, Philips, and Osram.
At LEDTEK, we exclusively use premium power supplies to ensure the performance and longevity of our lighting products.