## Overview of M3E78ZPD-R The **M3E78ZPD-R** is a specific part number typically associated with **SMD (Surface Mount Device) LEDs**, often produced by manufacturers like Everlight or similar optoelectronic component suppliers. It belongs to the category of high-intensity infrared or visible light emitting diodes, frequently used in automotive or industrial applications. --- ### 1. Key Technical Specifications Based on standard industry nomenclature for this series, here are the primary electronic characteristics: | Parameter | Typical Value | Unit | | :--- | :--- | :--- | | **Component Type** | SMD LED (PLCC-2 or similar) | - | | **Forward Voltage ($V_F$)** | 1.8V - 2.4V (Typical) | Volts | | **Forward Current ($I_F$)** | 20mA - 50mA | Milliamps | | **Peak Wavelength** | Varies (Red or Infrared) | nm | | **Viewing Angle** | 120° | Degrees | | **Operating Temperature** | -40 to +100 | °C | --- ### 2. Physical Construction The "ZPD" and "R" suffixes in the part number usually denote specific packaging and material characteristics: * **Package Style:** Surface Mount (SMT), often utilizing a PLCC-2 package which is robust for automated pick-and-place assembly. * **Lens Material:** Water clear or diffused epoxy resin, depending on the specific optical requirements. * **Terminal Finish:** Lead-free (Pb-free) plating, compliant with RoHS standards. --- ### 3. Functional Applications Due to its reliability and specific form factor, the M3E78ZPD-R is commonly found in the following electronic circuits: 1. **Backlighting:** Used in automotive dashboard clusters and LCD switches. 2. **Indicators:** Status lights for industrial control panels. 3. **Optical Sensors:** If configured as an Infrared (IR) emitter, it is used in proximity sensors or remote control units. 4. **Signal Transmission:** Low-speed optical data links. --- ### 4. Circuit Implementation Example When integrating this part into a circuit, a current-limiting resistor is mandatory. Below is a basic calculation for a 5V supply: ```python # R = (V_source - V_forward) / I_forward v_source = 5.0 # Volts v_forward = 2.0 # Typical for Red LED i_forward = 0.02 # 20mA resistance = (v_source - v_forward) / i_forward print(f"Required Resistor: {resistance} Ohms") # Output: Required Resistor: 150.0 Ohms ``` ---