The **LR-534-R/B** is a common part number typically associated with **Bicolor LED Lamps** (Red/Blue). These components are widely used as status indicators in consumer electronics, network equipment, and control panels. ### 1. General Specifications The LR-534 series generally features a 5mm (T1-3/4) through-hole package. | Parameter | Red Specification (R) | Blue Specification (B) | | :--- | :--- | :--- | | **Material** | GaAlAs / GaAsP | GaN / InGaN | | **Wavelength** | ~625 nm - 660 nm | ~465 nm - 475 nm | | **Forward Voltage ($V_f$)** | 1.8V - 2.4V | 3.0V - 3.6V | | **Forward Current ($I_f$)** | 20mA | 20mA | | **Luminous Intensity** | 50 - 150 mcd | 100 - 300 mcd | | **Viewing Angle** | 30° - 60° | 30° - 60° | --- ### 2. Internal Configuration Depending on the specific manufacturer (such as LITE-ON or local equivalents), the LR-534-R/B usually comes in one of two internal wiring configurations: #### A. Common Cathode (3 Pins) * **Pin 1:** Anode for Red * **Pin 2:** Common Cathode (Ground) * **Pin 3:** Anode for Blue #### B. Bipolar / Bi-directional (2 Pins) * The Red and Blue chips are connected in parallel with opposite polarities. * Current in one direction lights up **Red**. * Current in the reverse direction lights up **Blue**. * Rapidly switching (PWM) creates a **Purple/Magenta** blend. --- ### 3. Key Electronic Characteristics * **Diffused vs. Water Clear:** The "LR" prefix often suggests a diffused lens (milky white) which spreads light evenly for indicator use, rather than a clear lens used for high-intensity beams. * **Reverse Voltage:** Typically rated at 5V. Exceeding this can damage the LED junction. * **Operating Temperature:** Generally rated between -40°C to +85°C. --- ### 4. Typical Application Circuit When connecting to a microcontroller (like an Arduino), you must use current-limiting resistors. Since Blue LEDs have a higher forward voltage, the resistor values should differ to maintain equal brightness. ```cpp // Example: Resistor Calculation for 5V Supply // Red: (5V - 2.0V) / 0.020A = 150 Ohms // Blue: (5V - 3.2V) / 0.020A = 90 Ohms (Use 100 Ohm) ```