The **C566T-RFS** is a high-brightness, oval-shaped Red LED manufactured by **Cree LED** (now part of SGH). It is specifically designed for full-color video signs and outdoor passenger information signs. --- ### ## Technical Specifications Below are the primary electronic and optical characteristics of the C566T-RFS: | Feature | Specification | | :--- | :--- | | **Color** | Red | | **Dominant Wavelength** | 621 nm - 630 nm | | **Luminous Intensity** | 1100 - 3000 mcd (millicandela) | | **Forward Current ($I_F$)** | 50 mA (Maximum) | | **Forward Voltage ($V_F$)** | 2.1V (Typical) / 2.6V (Maximum) | | **Viewing Angle** | 70° (Horizontal) / 35° (Vertical) | | **Lens Appearance** | Red Diffused | | **Package Type** | 5mm Round (Oval base) | --- ### ### Key Electronic Components & Features 1. **Material Composition (AlInGaP):** The LED uses **Aluminum Indium Gallium Phosphide (AlInGaP)** technology. This material is chosen for red LEDs because it offers high luminous efficiency and stable performance across temperature fluctuations. 2. **Radiation Pattern (Oval Shape):** Unlike standard round LEDs, the "T" series features an oval-shaped lens. This creates a **wide horizontal viewing angle (70°)** and a **narrow vertical viewing angle (35°)**. This is electronically efficient for outdoor signage because it directs light toward the viewers on the ground/street rather than wasting light towards the sky. 3. **Reverse Voltage Protection:** The device is rated for a maximum reverse voltage ($V_R$) of **5V**. Designers must ensure that circuit spikes do not exceed this threshold to prevent diode breakdown. 4. **Standoff Options:** The "S" in the part number suffix often indicates the inclusion of **standoffs** on the leads. These are small protrusions that keep the LED body elevated from the PCB during soldering, allowing for better heat dissipation and easier cleaning. --- ### ### Typical Application Circuit When integrating the C566T-RFS into an electronic system, a current-limiting resistor is required. ```cpp // Example Calculation for a 5V System: // Source Voltage (Vs) = 5V // Forward Voltage (Vf) = 2.1V // Target Current (If) = 20mA (0.02A) R = (Vs - Vf) / If R = (5V - 2.1V) / 0.02A R = 145 Ohms (Use 150 Ohm standard resistor) ```