The **LOR3E-R0075-G** is a high-precision, low-resistance **Current Sense Resistor** (also known as a Shunt Resistor). These components are critical in power management circuits for measuring current flow by detecting the voltage drop across a known resistance. --- ## 1. Technical Specifications The part number follows a specific nomenclature typically associated with manufacturers like **LRC (Leshan Radio Company)** or similar high-power resistor specialists. | Parameter | Value / Specification | | :--- | :--- | | **Component Type** | Current Sense Resistor (Metal Strip/Alloy) | | **Resistance Value** | 7.5 mΩ (0.0075 Ω) | | **Resistance Tolerance** | ±2% (indicated by the 'G' suffix) | | **Package / Case** | 2512 (Inch) / 6432 (Metric) | | **Technology** | Metal Plate / Low TCR Alloy | | **Power Rating** | Usually 2W to 3W (standard for 2512 size) | --- ## 2. Part Number Breakdown To understand the specific attributes, we can deconstruct the code: * **LOR**: Series prefix (Low Ohmic Resistor / Metal Strip). * **3E**: Power rating / Size code (commonly associated with the **2512** surface mount footprint). * **R0075**: The resistance value. "R" acts as a decimal point. `0.0075 Ohms` = `7.5 mΩ`. * **G**: Tolerance code. In the resistor world, **G = ±2%**. (Note: F = ±1%, J = ±5%). --- ## 3. Key Electronic Features ### Low Temperature Coefficient (TCR) Because these are made from metal alloys (like Manganin or NiCr), the resistance stays stable even as the component heats up due to high current. This ensures measurement accuracy across temperature ranges. ### High Power Dissipation The 2512 package is physically large for an SMD component, allowing it to dissipate the heat generated by the $I^2R$ power loss without failing. ### Low Inductance Unlike wire-wound resistors, the metal plate construction has very low parasitic inductance, making it suitable for high-frequency switching power supplies. --- ## 4. Common Applications This specific resistance value (7.5 mΩ) is frequently found in: 1. **Battery Management Systems (BMS):** Monitoring charge and discharge cycles in Li-ion packs. 2. **DC-DC Converters:** Providing feedback for current-mode control loops. 3. **Motor Control:** Detecting "over-current" conditions to protect the motor and driver. 4. **Power Inverters:** Measuring output current for load balancing. --- ## 5. Usage Circuit Example In a typical circuit, the resistor is placed in series with the load. ```text [Power Source] ----+---- [LOR3E-R0075-G] ----+---- [Load] ---- [GND] | | +----(To Op-Amp / ADC)----+ ``` The voltage $V$ measured across the resistor is converted to current $I$ using Ohm’s Law: $$I = \frac{V_{measured}}{0.0075}$$