The designation **11N-R** typically refers to a specific series of **NTC (Negative Temperature Coefficient) Thermistors**. These are passive electronic components used for temperature sensing or inrush current limiting. --- ### 1. What is an 11N-R Thermistor? A thermistor is a type of resistor whose resistance value changes significantly with temperature. In the case of the **11N-R** series (often associated with manufacturers like THINKING or DSC): * **11**: Usually indicates the disk diameter (e.g., 11mm). * **N**: Stands for NTC (Negative Temperature Coefficient), meaning resistance decreases as temperature increases. * **R**: Often signifies "RoHS Compliant" or a specific resistance characteristic. ### 2. Key Technical Specifications While exact specs vary by the full part number (e.g., SCK-11N5), common characteristics include: | Feature | Description | | :--- | :--- | | **Material** | Metal oxide ceramic (manganese, cobalt, nickel) | | **Coating** | Phenolic resin or Silicone (high temperature resistance) | | **Response Time** | Fast (typically < 60 seconds in air) | | **Operating Temp** | -40°C to +170°C (standard range) | | **Function** | Inrush current suppression or temperature compensation | --- ### 3. Primary Functions #### A. Inrush Current Limiting When a device (like a Power Supply) is first turned on, there is a massive surge of current. 1. **At Start:** The 11N-R is cold and has **high resistance**, blocking the surge. 2. **During Operation:** The current heats the thermistor, its **resistance drops** to nearly zero, allowing the circuit to run efficiently. #### B. Temperature Sensing Used in thermostats or battery chargers to monitor heat levels. As the device gets hotter, the resistance change is measured by a microcontroller to trigger cooling fans or safety shut-offs. ### 4. Common Applications * **Switching Mode Power Supplies (SMPS)** * **Electric Motors** * **LED Drivers** * **Uninterruptible Power Supplies (UPS)** * **Household Appliances** (Refrigerators, Air Conditioners) --- ### 5. Identification Example If you see a part labeled `SCK 103 11N`, it breaks down as: * **SCK:** Series name. * **103:** Resistance at 25°C ($10 \times 10^3 = 10k\Omega$). * **11:** Disk size (11mm). * **N:** NTC type.