The **D439-R1LL-G2** is a specific model of a **Miniature Snap-Action Switch** (often referred to as a microswitch) manufactured by **Cherry** (now part of **ZF Switches & Sensors**). These switches are known for their high reliability and are commonly used in industrial control, automotive, and appliance applications. --- ### 1. Key Technical Specifications The model number "D439-R1LL-G2" defines the electrical and mechanical characteristics of the component. | Specification | Value/Description | | :--- | :--- | | **Series** | D4 Series (High-capacity miniature) | | **Contact Configuration** | SPDT (Single Pole Double Throw) | | **Current Rating** | 15A at 250VAC | | **Actuator Type** | Long Straight Lever (LL) | | **Terminal Type** | Quick Connect / Solder Terminals (4.8mm x 0.5mm) | | **Operating Force** | Approximately 45cN (depending on lever length) | | **Contact Material** | AgNi (Silver Nickel) | --- ### 2. Breakdown of the Model Code To understand the "electronic parts" of this switch, it helps to decode the part number: * **D4**: The base series, indicating a miniature housing size. * **3**: Indicates the electrical rating/contact gap (Standard force, high current). * **9**: Specific internal configuration or regional variant. * **R1**: Terminal style (usually indicates 4.8mm QC terminals). * **LL**: **Long Lever**. This is the mechanical arm that triggers the internal spring mechanism. * **G2**: The specific variant of the lever or the positioning of the mounting holes. --- ### 3. Internal Components & Materials The switch consists of several critical electronic and mechanical parts: 1. **Stationary Contacts:** Made of Silver Nickel (AgNi) for excellent conductivity and resistance to "welding" under high electrical loads. 2. **Movable Blade:** A beryllium copper spring that "snaps" between positions to ensure rapid contact separation, which minimizes electrical arcing. 3. **Housing:** Made of PET (Polyethylene Terephthalate) or similar thermoplastic, designed to be flame retardant (UL94V-0 rated). 4. **Plunger/Actuator:** The interface between the external lever and the internal spring mechanism. --- ### 4. Circuit Diagram (SPDT) The D439 series typically features three terminals: * **COM (Common):** The input terminal. * **NC (Normally Closed):** Connected to COM when the lever is NOT pressed. * **NO (Normally Open):** Connected to COM when the lever IS pressed. ```text [COM] / (NC)o o(NO) ```