## Technical Overview of QBLP617-R The **QBLP617-R** is a high-brightness Red Surface Mount Device (SMD) LED manufactured by **QT-Brightek**. It belongs to the 0805 package family, which is one of the most common sizes for indicator lights in consumer electronics and industrial boards. --- ### 1. Key Technical Specifications The following table highlights the critical electrical and optical characteristics of the QBLP617-R: | Parameter | Specification | Unit | | :--- | :--- | :--- | | **Emitted Color** | Red | - | | **Package Size** | 0805 (2.0 x 1.25 x 0.8 mm) | Metric | | **Peak Wavelength** | 630 - 645 | nm | | **Luminous Intensity** | 80 - 160 (typical) | mcd | | **Forward Voltage ($V_f$)** | 1.8 - 2.4 | V | | **Forward Current ($I_f$)** | 20 (Standard) | mA | | **Viewing Angle** | 140 | Degrees | | **Lens Type** | Water Clear | - | --- ### 2. Physical Design and Dimensions The "617" series refers to the specific 0805 form factor. It is designed for automated "pick and place" assembly. * **Footprint:** Small enough for high-density PCB layouts. * **Polarity:** Usually marked with a green T-bar or a notch on the underside of the SMD body to indicate the Cathode. * **Material:** Built using **AlGaInP** (Aluminum Gallium Indium Phosphide) technology, which allows for high efficiency and brightness in the red spectrum. --- ### 3. Application Use Cases Because of its small size and reliable output, the QBLP617-R is used in various electronic circuits: 1. **Status Indicators:** Power ON/OFF lights for routers, laptops, and chargers. 2. **Backlighting:** Illuminating membrane switches or LCD panels. 3. **Consumer Electronics:** Wearable devices and handheld gadgets. 4. **Signal Logic:** Debugging LEDs on development boards (like Arduino or ESP32 shields). --- ### 4. Typical Circuit Integration To use the QBLP617-R with a 5V microcontroller (like an Arduino), you must use a current-limiting resistor to prevent burning out the LED. **Calculation Example:** Assuming a 5V source, a 2.0V Forward Voltage, and a desired 20mA current: `R = (V_source - V_forward) / I_forward` `R = (5V - 2.0V) / 0.020A = 150 Ohms` ```c // Example: LED Pin Definition #define STATUS_LED_PIN 13 void setup() { pinMode(STATUS_LED_PIN, OUTPUT); } void loop() { digitalWrite(STATUS_LED_PIN, HIGH); // LED On delay(1000); digitalWrite(STATUS_LED_PIN, LOW); // LED Off delay(1000); } ```