The **RL1005-2-R100J** is a high-precision, low-resistance surface-mount (SMD) resistor, typically used for **current sensing** applications. It is part of the RL series manufactured by companies like Susumu or Bourns. --- ## 1. Part Number Breakdown The part number follows a specific nomenclature that defines its physical and electrical characteristics: | Component | Code | Description | | :--- | :--- | :--- | | **Series** | RL1005 | RL series, 1005 Metric size (0402 Imperial) | | **Terminal** | 2 | 2-terminal configuration | | **Resistance** | R100 | 0.100 $\Omega$ (100 m$\Omega$) | | **Tolerance** | J | $\pm 5\%$ | --- ## 2. Technical Specifications The RL1005 series is designed to handle power in a very small footprint while maintaining stability. | Parameter | Value | | :--- | :--- | | **Resistance Value** | 0.1 $\Omega$ (100 m$\Omega$) | | **Package Size** | 1005 Metric / 0402 Imperial (1.0mm x 0.5mm) | | **Power Rating** | 0.125W (1/8 W) typical | | **Tolerance** | $\pm 5\%$ | | **Temperature Coefficient (TCR)** | Typically 0 ~ +350 ppm/°C (varies by sub-series) | | **Operating Temp** | -55°C to +125°C | --- ## 3. Key Features and Applications ### Features * **Low Resistance:** Specifically engineered for low ohmic values where standard thick-film resistors are inaccurate. * **Metal Foil/Film Technology:** Often utilizes long-side electrodes or specific metal-glaze materials to reduce parasitic inductance. * **Compact Design:** The 0402 footprint is ideal for high-density mobile electronics. ### Common Applications 1. **Current Sensing:** Used to monitor current flow by measuring the voltage drop across the resistor ($V = I \times R$). 2. **Power Management:** Found in DC-DC converters and battery management systems (BMS). 3. **Mobile Devices:** Used in smartphones and tablets for battery gas-gauging. 4. **Over-current Protection:** Sensing excessive current to trigger safety shutdowns. --- ## 4. Typical Internal Construction The device is usually constructed using a ceramic substrate with a resistive element printed or deposited on top. ```markdown [ Protective Coating ] [ Resistive Element ] <--- Metal Glaze or Foil [ Ceramic Substrate ] [ Inner Terminal ] [ Outer Solder Plate ] (Ni/Sn plating) ```