The **C4SMK-RJS-CT24QBB1** is a high-performance, through-hole Oval LED manufactured by **Cree LED** (formerly Cree Inc.). It is part of the Screen Master series, specifically designed for outdoor video screens and digital signage. --- ### 1. Key Technical Specifications Below are the primary electronic and optical characteristics of this specific component: | Parameter | Specification | | :--- | :--- | | **Color** | Red | | **Dominant Wavelength** | 621 nm (Typical) | | **Luminous Intensity** | 550 - 1520 mcd | | **Viewing Angle** | 110° (Horizontal) / 50° (Vertical) | | **Forward Current ($I_F$)** | 50 mA (Maximum) | | **Forward Voltage ($V_F$)** | 2.1 V (Typical) | | **Lens Type** | Tinted / Diffused | | **Package Shape** | 4mm Oval | --- ### 2. Functional Design Features The "C4SMK" series is engineered for durability and visibility in sunlight. * **Oval Spatial Pattern:** The asymmetric viewing angle (110° x 50°) is designed to provide a wide viewing area for pedestrians and drivers while minimizing light wasted toward the sky or the ground. * **UV Resistance:** The epoxy resin contains UV inhibitors to prevent the lens from yellowing or becoming brittle when exposed to direct sunlight over long periods. * **Standoff Pins:** The "K" in the part number often indicates the presence of standoffs on the leads, which helps in PCB cleaning and ensures uniform height during manual or wave soldering. --- ### 3. Part Number Breakdown (Nomenclature) To understand the specific electronic binning of this part, we can decode the suffix: | Code | Meaning | Description | | :--- | :--- | :--- | | **C4SMK** | Series | 4mm Oval LED with Standoffs | | **RJS** | Color | Red (AllnGaP technology) | | **CT24QBB1** | Binning | Defines the specific intensity range and color sub-bins | --- ### 4. Typical Applications Because of its high brightness and reliability, this part is commonly found in: 1. **Electronic Passenger Information:** Bus and train station arrival/departure boards. 2. **Outdoor Video Displays:** Large-scale RGB screens for advertising. 3. **Variable Message Signs (VMS):** Highway traffic alerts and speed limit displays. --- ### 5. Connection Diagram (General Concept) When integrating this LED into a circuit, it is driven by a constant current source or a current-limiting resistor. ```cpp // Example: Calculating a Current Limiting Resistor // Supply Voltage (Vcc) = 5V // Forward Voltage (Vf) = 2.1V // Target Current (If) = 20mA (0.02A) R = (Vcc - Vf) / If R = (5V - 2.1V) / 0.02A R = 145 Ohms (Use 150 Ohm standard resistor) ```