The **ALR-322-R** is a specific electronic component typically categorized as a **Surface Mount Device (SMD) LED**, specifically a right-angle (side-view) chip LED. These are commonly used in backlighting applications where space is constrained and light must be directed parallel to the PCB. --- ### 1. Key Technical Specifications Below is a breakdown of the typical electronic characteristics for the ALR-322-R series: | Parameter | Specification (Typical) | | :--- | :--- | | **Component Type** | Right-Angle SMD LED | | **Package Size** | 3.2mm x 1.0mm x 1.5mm | | **Forward Voltage ($V_F$)** | 2.0V - 3.2V (Color dependent) | | **Forward Current ($I_F$)** | 20mA (Standard) | | **Luminous Intensity** | 15mcd - 100mcd (Depending on Binning) | | **Viewing Angle** | 120° - 140° | | **Operating Temp** | -40°C to +85°C | --- ### 2. Physical Construction & Pinout The "R" in the part number often signifies the **Right-Angle** orientation. * **Lens:** Usually clear or water-clear epoxy to maximize light output. * **Terminals:** Gold-plated or Tin-plated solder pads located on the side/bottom for surface mounting. * **Polarity:** Marked by a notch or a green line on the cathode side of the package. --- ### 3. Circuit Integration When designing a circuit with the ALR-322-R, it is essential to use a current-limiting resistor to prevent thermal runaway. #### Example Calculation: To run a Red ALR-322 ($V_F = 2.0V$) on a 5V rail at 15mA: ```text R = (V_source - V_forward) / I_forward R = (5V - 2.0V) / 0.015A R = 200 Ohms ``` --- ### 4. Common Applications Due to its unique side-firing orientation, this part is used in: * **LCD Backlighting:** Edge-lighting for small displays. * **Status Indicators:** Low-profile indicators on the edge of a PCB. * **Light Pipes:** Coupling light into plastic fiber optic pipes. * **Handheld Devices:** Mobile phones and wearable tech where vertical height is limited.