How to Set the Thermal Resistance of COB?
Release date: 2017-11-15
Source: External Source
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When simulating a COB light source, you often find its thermal resistance specified in the datasheet. For example, if it's listed as 5°C/W, and the power required is 14W, the temperature rise would be around 70°C. However, this is just a starting point. The actual thermal performance depends on several factors including the design of the heat sink, the material used, and the surrounding environment.
1. How is the final thermal resistance calculated?
The final thermal resistance is usually determined by combining the internal thermal resistance of the COB with the external thermal resistance from the heat sink and the ambient conditions. This can be done through simulation tools like ANSYS or by conducting real-world tests.
2. If the COB light source is ceramic, what thermal conductivity should be set?
Ceramic substrates generally have higher thermal conductivity compared to traditional materials. For instance, aluminum nitride (AlN) has a thermal conductivity of around 180 W/m·K, which is much better than alumina (Al₂O₃), which is about 20–30 W/m·K. When using ceramic, you should adjust the thermal resistance accordingly based on the material’s properties.
3. What area should be considered? The largest area of the COB or the effective area of the LED chip?
In most cases, the effective area refers to the surface where heat is generated and transferred. This is typically the area directly under the LED chip rather than the entire COB footprint. Using the correct area ensures more accurate thermal modeling.
When performing finite element analysis, ANSYS is a popular choice for thermal simulations. However, real-world testing also plays a crucial role. Environmental factors such as airflow, ambient temperature, and placement can significantly affect the results. Additionally, the accuracy of test points and the potential for measurement errors can lead to discrepancies between simulated and actual outcomes.
It's recommended to use empirical values or combine them with ANSYS simulations for a more reliable approach. Physical testing and evaluation are essential to validate the thermal performance of the COB in real applications.
Tag: How to Set the Thermal Resistance of COB?
Building Cables
they are suitable for power & lighting circuits and building wiring. Also suitable for use as an earth wire the internal wiring of appliances and apparatus.
Essential Guide to Building Wires for Home Safety and Functionality
A safe and functional electrical system is foundational to any modern structure, and "Building Wire And Cable" provide the vital pathways for electricity to travel. These "Building Wires" are also commonly referred to as "House Wiring" and are essential for bringing power to lights, appliances, outlets, and more. Choosing the right "Building Cables" for your home is a critical step for ensuring the safety of the occupants, the efficiency of electricity usage, and the longevity of the electrical system.
In the construction of "House Wiring," several insulated copper conductors, usually encased in a protective jacket, are the norm. The type of material used for the jacket, the conductor size, and the number of conductors define a cable's appropriateness for given applications.
Let`s examine the main components:
Insulation: Wrapping each conductor is a layer of insulation, crucial for preventing electrical leaks and maintaining safety. PVC, known for its cost-effectiveness and resistance to moisture, is widely used, as is THHN insulation, which can handle higher operating temperatures.
Conductors: Copper is typically used as the primary material for conductors in "Building Wire" due to its excellent electrical conductivity and durability.
Jackets: The outer layer of "Building Cables" protects the conductors from damage, moisture, and external conditions. Jackets are often made of PVC for its combination of affordability and resilience; other materials, like nylon, are available for those seeking higher strength and pliability.
Important factors to consider when selecting the appropriate "Building Cables" include:
Circuit Type: "Building Wire" for branch circuits, which power outlets and fixtures, is typically different from feeder circuits that transport power from the main supply to various parts of the house.
Application: "Building Cables" must be chosen according to their ability to carry required currents. This means that wiring for heavy-duty appliances will need thicker conductors.
Location: The installation environment influences the selection of "House Wiring," as some are specifically designed with features for use in damp conditions or outdoor applications.
Wire Gauge: Expressed in AWG , wire gauge affects current-carrying capacity, with larger numbers denoting thinner wires.
Popular "Building Wire" varieties include:
NM-B Cable (Nonmetallic-Sheathed): Suited for indoor use, this cable is adaptable and commonly employed in branch circuitry within protected environments.
THHN/THWN Cable: These cables are designed to resist higher temperatures and are suitable for a multitude of settings, including feeders and branch circuits in both dry or damp areas.
UF Cable (Underground Feeder): Specifically designed for subterranean installation, UF cables are equipped with waterproofing to handle these demanding conditions.
Always allow a certified electrician to execute electrical installations to assure conformity with safety norms and efficiency of installation. The local building codes dictate the specifications and installation techniques, making professional consultation a key element in the safety of your electrical system.
- Standard applied: IEC60227, BS 6004
- U0/U: 450/750V
- Certification: CE
- Flame retardant or fire resistance or Low smoking and Halogen free or other property can be available
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