The **QBLP651-R** is a specific surface-mount technology (SMT) LED manufactured by **QT-Brightek**. It belongs to the 1206 package size family and is primarily used for status indication in various electronic circuits. --- ### 1. Key Technical Specifications The following table summarizes the primary electrical and optical characteristics of the QBLP651-R: | Parameter | Specification | | :--- | :--- | | **Emitted Color** | Red | | **Package Size** | 1206 (3.2 x 1.6 x 1.1 mm) | | **Peak Wavelength** | 630 nm | | **Luminous Intensity** | 80 - 150 mcd @ 20mA | | **Forward Voltage ($V_F$)** | 2.0V (Typical) / 2.5V (Max) | | **Forward Current ($I_F$)** | 20 mA (Standard Operating) | | **Viewing Angle** | 140° | | **Lens Type** | Water Clear | --- ### 2. Physical Design and Packaging * **Form Factor:** The **1206 package** is relatively large compared to 0603 or 0402 LEDs, making it easier to solder by hand during prototyping while remaining compact for automated SMT production. * **Orientation:** The part features a polarity mark (usually a green notch or T-mark on the bottom) to identify the **Cathode (-)** terminal. * **Materials:** Built using AlGaInP (Aluminium Gallium Indium Phosphide) technology, which provides high efficiency for red spectrum light. --- ### 3. Application Use Cases Because of its reliability and standard footprint, the QBLP651-R is commonly found in: 1. **Industrial Controls:** Status indicators on DIN rail equipment. 2. **Consumer Electronics:** Power-on lights for routers, chargers, and appliances. 3. **Medical Devices:** Visual alerts for patient monitoring systems. 4. **Automotive:** Dashboard backlighting and button illumination. --- ### 4. Implementation Example (Basic Circuit) To use this LED with a 5V DC power supply, a current-limiting resistor is required. ```cpp // Calculation for Current Limiting Resistor (R) // R = (V_supply - V_forward) / I_forward // R = (5.0V - 2.0V) / 0.02A // R = 150 Ohms ```