The **C4SMR-RJY** is a high-performance, through-hole LED manufactured by **Cree LED (Wolfspeed)**. It belongs to the Screen Master® series, specifically designed for outdoor signage and electronic displays. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Color** | Red | | **Dominant Wavelength** | 621 nm (Typical) | | **Luminous Intensity** | 1100 - 3000 mcd | | **Lens Type** | Oval / Diffused / Tinted | | **Viewing Angle** | 70° (Horizontal) / 35° (Vertical) | | **Forward Current** | 50 mA (Maximum) | | **Forward Voltage** | 2.1V (Typical) | | **Mounting Type** | Through-Hole (Radial) | --- ### 2. Physical and Electronic Characteristics #### A. Oval Shape Design The LED features an oval-shaped lens. This is a deliberate electronic design choice to create a wide horizontal viewing angle (70°) and a narrow vertical angle (35°). This ensures the light is directed toward the audience (pedestrians/drivers) rather than wasting light pointing at the sky or the ground. #### B. Material Composition * **Substrate:** Uses AllnGaP (Aluminium Indium Gallium Phosphide) technology. * **Encapsulation:** The epoxy contains UV inhibitors, which prevents the plastic from yellowing or becoming brittle when exposed to direct sunlight over long periods. #### C. Electrical Efficiency The C4SMR-RJY is optimized for low power consumption while maintaining high brightness. With a typical forward voltage of only **2.1V**, it is easily integrated into standard 3.3V or 5V logic circuits using a simple current-limiting resistor. --- ### 3. Primary Applications Due to its robust construction and specific light pattern, it is commonly found in: 1. **Full-Color Outdoor Signs:** Large-scale LED billboards. 2. **Variable Message Signs (VMS):** Highway and traffic management boards. 3. **Petrol Station Price Signs:** Digital number displays for fuel costs. 4. **Amusement Park Displays:** Decorative lighting requiring high visibility. --- ### 4. Schematic Considerations When designing a PCB for the C4SMR-RJY, observe the following: * **Polarity:** The longer lead is typically the Anode (+), and the shorter lead/flat side of the housing is the Cathode (-). * **Heat Dissipation:** While it is a low-power component, dense clusters of these LEDs in a sign require adequate ventilation to prevent thermal runaway.