The **S03-02-R** is a specific electronic component primarily identified as a **Surface Mount (SMT) Spring Contact**, often referred to as a "Shield Finger" or "Grounding Contact." These parts are manufactured by companies like **Harwin** and are critical for grounding and EMI (Electromagnetic Interference) shielding in compact electronic devices. --- ### 1. Key Technical Specifications Below are the typical technical attributes for the S03-02-R series: | Feature | Specification | | :--- | :--- | | **Component Type** | SMT Spring Contact / Shield Finger | | **Material** | Beryllium Copper or Phosphor Bronze | | **Plating** | Gold or Tin (R-suffix often denotes Gold) | | **Height (Uncompressed)** | 2.00mm (Typical) | | **Mounting Style** | Surface Mount (SMT) | | **Packaging** | Tape and Reel (for automated assembly) | --- ### 2. Functional Purpose The S03-02-R serves three primary roles within a circuit board assembly: 1. **Grounding:** It provides a low-resistance electrical path between the PCB and another metal chassis or component (like a battery or antenna). 2. **EMI Shielding:** It is used to connect metal "cans" or shields to the ground plane to prevent radio frequency interference. 3. **Mechanical Buffer:** Because it is spring-loaded, it can absorb mechanical tolerances and vibrations while maintaining a constant electrical connection. --- ### 3. Physical Design and Dimensions The "02" in the part number often relates to the physical height. These components are designed with a **"C" shape** or a **"Cantilever" design**: * **Footprint:** Small rectangular pads designed for reflow soldering. * **Contact Point:** A rounded tip to allow for sliding contact without snagging. * **Travel:** It is designed to be compressed. Over-compression can lead to permanent deformation (set), so engineers must calculate the working height carefully. --- ### 4. Typical Applications * **Mobile Devices:** Connecting antennas to the main logic board. * **Laptops/Tablets:** Grounding the LCD frame to the motherboard. * **Automotive Electronics:** Providing vibration-resistant grounding in infotainment systems. * **Wearables:** Compact power connections for charging docks. --- ### 5. Selection Considerations When using the S03-02-R, engineers must consider: * **Working Height:** The distance between the PCB and the mating surface should be within the spring's elastic range. * **Current Rating:** Typically supports small currents (0.5A to 2A); not suitable for high-power transmission. * **Solderability:** Ensure the footprint matches the manufacturer's land pattern to prevent "tombstoning" during reflow.