The **LTL-R42M12NH51** is a specific electronic component typically classified under **Optoelectronics**, specifically as an **Infrared (IR) LED** or **Phototransistor** assembly often used in proximity sensing or optical switching. Below is a detailed technical breakdown of its characteristics and functions. --- ### 1. General Specifications While specific datasheets are proprietary to the manufacturer (often Lite-On), this part number follows standard naming conventions for high-performance optical sensors. | Attribute | Typical Description | | :--- | :--- | | **Component Type** | Optical Emitter/Receiver (IR LED) | | **Wavelength** | Usually 940nm (Peak emission) | | **Mounting Type** | Surface Mount (SMD) | | **Application** | Proximity sensing, smoke detection, or touch screens | | **Operating Temperature** | -40°C to +85°C | --- ### 2. Internal Electronic Structure The part is designed to convert electrical energy into light (infrared spectrum) or vice versa. * **The LED Die:** A Gallium Arsenide (GaAs) or Aluminum Gallium Arsenide (AlGaAs) semiconductor chip. When current flows through the P-N junction, it emits infrared light. * **Encapsulation:** The "M12" and "NH51" suffixes often refer to the mold type and the lens color/tint. Usually, it features a clear or black-tinted epoxy resin to filter out visible light interference. * **Lead Frame:** Provides the electrical connection points for soldering onto a PCB. --- ### 3. Key Technical Parameters To integrate this part into a circuit, an engineer must consider these electrical limits: 1. **Forward Current ($I_F$):** The amount of current allowed to flow through the diode (typically 20mA - 50mA). 2. **Forward Voltage ($V_F$):** The voltage drop across the part, usually ranging from 1.2V to 1.5V. 3. **Radiant Intensity:** Measured in mW/sr (milliwatts per steradian), indicating how "bright" the IR output is. 4. **Viewing Angle:** The angle at which the light intensity drops to 50% of its peak. --- ### 4. Typical Application Circuit A common way to drive this component is using a simple current-limiting resistor circuit: ```cpp // Schematic Logic: // [VCC] --- [Resistor (R)] --- [LTL-R42M12NH51 (Anode)] // [LTL-R42M12NH51 (Cathode)] --- [GND] // Formula to calculate Resistor (R): // R = (Vcc - Vf) / If ``` --- ### 5. Common Use Cases * **Industrial Sensors:** Detecting the presence of objects on a conveyor belt. * **Consumer Electronics:** Remote control signal transmission. * **Automotive:** Rain sensors or steering wheel grip detection. ---