The **W2SP-112-R** is a specific model within the series of high-performance electromechanical relays, typically associated with automotive and industrial switching applications. Below is a detailed breakdown of its electronic characteristics and specifications. ### 1. Component Overview The W2SP-112-R is a **Miniature Automotive Power Relay**. Its primary function is to allow a low-power circuit (like a logic controller or switch) to control a high-current load (like a fuel pump, fan, or lighting system). ### 2. Technical Specifications | Feature | Specification | | :--- | :--- | | **Contact Arrangement** | 1 Form C (SPDT - Single Pole Double Throw) | | **Nominal Coil Voltage** | 12V DC | | **Contact Rating (Resistive)** | 20A to 30A (Typical) | | **Coil Resistance** | ~90 to 160 Ohms (depending on sensitivity) | | **Terminal Type** | PCB Mount (Through-hole) | | **Sealing** | Sealed/Wash tight (indicated by "S") | | **RoHS Compliant** | Yes (indicated by "R") | --- ### 3. Key Internal Parts & Functions The device operates through the interaction of several critical electronic and mechanical components: #### A. The Coil (Electromagnet) * **Winding:** Fine copper wire wound around a core. When 12V is applied, it creates a magnetic field. * **Sensitivity:** Designed to pull in the armature at a specific "Must Operate" voltage (usually around 7.2V to 8V for a 12V nominal coil). #### B. The Contacts * **Material:** Usually Silver Tin Oxide ($AgSnO_2$) or Silver Nickel ($AgNi$). These materials are chosen for their resistance to "welding" and electrical pitting under high-current arcs. * **SPDT Configuration:** Features a **Common (COM)**, **Normally Closed (NC)**, and **Normally Open (NO)** pin. #### C. The Armature and Spring * A mechanical lever that moves when the coil is energized. The spring ensures the contacts return to their default (NC) state once power is removed. --- ### 4. Part Number Breakdown (Nomenclature) Understanding the suffix and prefix helps in identifying the exact variant: * **W2:** Series designation (Automotive/Power). * **S:** Sealed construction (Protects against dust and flux during soldering). * **P:** PCB Terminal type. * **112:** "1" indicates the contact form (1 Pole); "12" indicates the **12V DC** coil rating. * **R:** Indicates **RoHS compliance** (Lead-free). ### 5. Common Applications * **Automotive Systems:** Power windows, central locking, seat adjustment, and cooling fans. * **Industrial Control:** Small motor control and PLC output buffering. * **Security:** Alarm system sirens and strobe triggers. ---