The **WMS2-1A-R** is a specific electronic component, typically identified as a **Surface Mount (SMD) Reed Switch** or a **Reed Sensor**. These devices are used to detect the presence of a magnetic field to open or close a circuit. Below is a detailed breakdown of its electronic characteristics and specifications. --- ### 1. General Specifications The "WMS" series generally refers to high-reliability reed sensors designed for automated assembly. | Feature | Specification (Typical) | | :--- | :--- | | **Contact Form** | Form A (Normally Open - SPST) | | **Mounting Type** | Surface Mount Device (SMD) | | **Switching Voltage** | 100V - 200V DC/AC (Max) | | **Switching Current** | 0.5A (Max) | | **Power Rating** | 10VA (Watts) | | **Termination** | Gull-wing or J-Lead (R suffix often denotes Tape & Reel) | --- ### 2. Physical Construction The device consists of two ferromagnetic blades (reeds) hermetically sealed in a glass envelope, which is then often over-molded in a plastic housing for SMD compatibility. * **Glass Encapsulation:** Protects contacts from oxidation and moisture. * **Contact Material:** Usually Rhodium or Ruthenium to ensure low contact resistance and long life. * **Molding:** The plastic body allows the component to be handled by pick-and-place machines and survive reflow soldering temperatures. --- ### 3. Operational Principles The WMS2-1A-R operates based on magnetism: 1. **Passive State:** Without a magnetic field, the two internal reeds are separated. The circuit is **Open**. 2. **Active State:** When a permanent magnet or electromagnet comes within the "Pull-In" range, the reeds become polarized and attract each other. The circuit is **Closed**. 3. **Release:** Once the magnet is removed, the inherent elasticity of the reeds causes them to snap back to the open position. --- ### 4. Application Examples Because of its small footprint and reliability, the WMS2-1A-R is commonly used in: * **Utility Meters:** For pulse counting in water or gas meters. * **Security Systems:** Detecting if a door or window is open. * **Mobile Devices:** Sensing "flip" or "clamshell" positions. * **Industrial Sensing:** Non-contact limit switching in harsh environments. --- ### 5. Part Number Breakdown (Typical) While naming conventions vary slightly by manufacturer (e.g., Standex Electronics or Winatic), the suffix usually follows this logic: ```text WMS2 - 1A - R | | | | | +-- Packaging (R = Tape & Reel) | +------- Contact Form (1A = 1 Form A / Normally Open) +-------------- Series Designator ```