The **KFS-21-R** is an electronic component commonly categorized as a **Limit Switch** or **Micro Switch**, often utilized in industrial machinery, home appliances, and safety interlock systems. --- ### 1. General Specifications The KFS-21-R is designed to convert mechanical motion into an electrical signal. Below are the typical electrical and physical parameters: | Parameter | Specification | | :--- | :--- | | **Switch Type** | Micro Switch / Limit Switch | | **Actuator Type** | Roller Lever (Long) | | **Contact Configuration** | SPDT (Single Pole Double Throw) | | **Rated Voltage** | 250V AC / 125V AC | | **Rated Current** | 10A to 15A (Depending on specific manufacturer) | | **Operating Force** | ~0.5N to 1.5N | | **Terminal Type** | Quick Connect / Solder Terminals | --- ### 2. Internal Electronic Structure The device operates on a **Single Pole Double Throw (SPDT)** mechanism, which includes three primary connection points: * **COM (Common):** The terminal where the input current enters. * **NC (Normally Closed):** The circuit is complete when the lever is at rest. * **NO (Normally Open):** The circuit is completed only when the lever is depressed. ### 3. Pinout Diagram Logic ```text [ Roller Lever ] / ____/____ | | | KFS-21-R| |_________| | | | COM NO NC ``` --- ### 4. Key Electronic Features 1. **Snap Action Mechanism:** The switch utilizes a spring-loaded mechanism that ensures rapid contact transfer regardless of the speed at which the lever is moved. This minimizes arcing and electrical wear. 2. **High Dielectric Strength:** Designed to withstand high voltage spikes without breaking down the insulation between contacts. 3. **Mechanical Life:** Typically rated for 1,000,000 cycles, making it highly reliable for repetitive tasks. ### 5. Common Applications * **Safety Interlocks:** Detecting if a microwave door or a 3D printer enclosure is closed. * **End-Stops:** Used in CNC machines to prevent the axis from moving beyond its physical limits. * **Industrial Automation:** Counting items on a conveyor belt as they pass and depress the roller. ---