The **W2SP-11D-R/UL** is a specific model of an **Electromagnetic Relay**, typically manufactured by companies like Song Chuan. It is designed for switching electrical loads in industrial and consumer electronics. Below is a detailed breakdown of its electronic components and specifications. ### 1. General Specifications The part number indicates a specific configuration regarding its poles, voltage, and safety ratings. | Feature | Specification | | :--- | :--- | | **Component Type** | Electromechanical Relay | | **Contact Form** | SPDT (1 Form C) | | **Coil Voltage** | 12V DC (Standard for the "11D" series) | | **Safety Approval** | UL (Underwriters Laboratories) Recognized | | **Mounting Type** | PCB (Through-hole) | --- ### 2. Key Internal Components An electromechanical relay consists of four primary electronic/mechanical parts: 1. **The Coil (Inductor):** * Acts as the input. When DC voltage (12V) is applied, it creates a magnetic field. * The "D" in the part number usually signifies a standard sensitive coil. 2. **The Armature:** * A pivoting piece of ferromagnetic metal that moves in response to the magnetic field created by the coil. 3. **The Contacts:** * **Common (COM):** The moving part. * **Normally Closed (NC):** Contacted when the coil is OFF. * **Normally Open (NO):** Contacted when the coil is ON. 4. **The Spring:** * Returns the armature to the default position once power is removed from the coil. --- ### 3. Electrical Characteristics These parameters are critical for circuit design to ensure the relay does not overheat or fail. | Parameter | Typical Value | | :--- | :--- | | **Contact Rating (Resistive)** | 10A to 16A @ 250VAC / 30VDC | | **Max Switching Voltage** | 250V AC / 110V DC | | **Contact Resistance** | < 100mΩ (Initial) | | **Dielectric Strength** | ~1,000V AC (between contacts) | | **Operating Temperature** | -40°C to +85°C | --- ### 4. Typical Applications Because of its compact size and UL rating, the W2SP series is commonly found in: * **Home Appliances:** Microwave ovens, washing machines, and HVAC controllers. * **Industrial Controls:** PLC output modules and timers. * **Automotive Electronics:** Power windows or light control (in 12V systems). --- ### 5. Circuit Design Tip: Flyback Diode When using the W2SP-11D-R/UL in a digital circuit (controlled by a transistor or MCU), you **must** include a flyback diode (e.g., 1N4148 or 1N4007) in parallel with the coil. This protects your sensitive electronics from the high-voltage spike (back EMF) generated when the relay coil is de-energized.