### Overview of the Cree C5SMA-RJS The **C5SMA-RJS** is a high-brightness, through-hole Red LED manufactured by **Cree LED** (formerly Wolfspeed). It belongs to the **Screen Master®** series, specifically designed for outdoor video screens, digital signage, and traffic signals due to its oval-shaped radiation pattern. --- ### Technical Specifications Below are the primary electronic and optical characteristics of the C5SMA-RJS: | Parameter | Specification | | :--- | :--- | | **Color** | Red | | **Dominant Wavelength** | 619 nm - 624 nm | | **Luminous Intensity** | 770 - 2130 mcd (millicandela) | | **Viewing Angle** | 100° Horizontal / 45° Vertical | | **Forward Current ($I_F$)** | 50 mA (Maximum) | | **Forward Voltage ($V_F$)** | 2.1V (Typical) / 2.6V (Maximum) | | **Reverse Voltage ($V_R$)** | 5V | | **Operating Temperature** | -40°C to +100°C | | **Lens Appearance** | Tinted, Diffused | --- ### Key Features 1. **Oval Spatial Radiation Pattern**: The 100°/45° viewing angle is engineered for wide horizontal visibility, making it ideal for large outdoor displays where viewers are positioned at various side angles. 2. **High Reliability**: Built with an epoxy resin that includes UV inhibitors, reducing the effects of long-term exposure to direct sunlight. 3. **Efficiency**: It uses **AlInGaP** (Aluminium Indium Gallium Phosphide) material technology, which provides high light output relative to power consumption. 4. **Standard Package**: It comes in a standard 5mm (T1 ¾) through-hole package with lead frames for traditional PCB mounting. --- ### Application Circuitry To operate the C5SMA-RJS safely, a current-limiting resistor must be used. Below is a basic calculation for a 5V supply: #### Resistor Calculation To run the LED at a safe **20mA** ($0.02A$) using a **5V** power source: * **Formula**: $R = (V_{source} - V_F) / I_F$ * **Calculation**: $R = (5V - 2.1V) / 0.02A = 145 \Omega$ * **Suggested Standard Resistor**: $150 \Omega$ #### Basic Schematic Layout ```text [5V Source] --- [150 Ohm Resistor] --- [Anode (+) LED Cathode (-)] --- [Ground] ``` --- ### Common Applications * **Outdoor Video Displays**: Large-scale LED billboards. * **Variable Message Signs (VMS)**: Highway and traffic information boards. * **Petrol Station Signs**: Digital price displays. * **Amusement Lighting**: Durable lighting for theme parks.