The part number **47LAC-1D2B-R** typically refers to a high-precision **Chassis Mount Resistor**, often utilized in industrial and power electronics. It is part of a series (likely from manufacturers like Arcol or similar high-power resistor specialists) designed for heat dissipation through a metal housing. ### 1. Component Overview This component is a wirewound resistor encased in an aluminum housing. The housing allows the resistor to be bolted to a chassis or heat sink, significantly increasing its power-handling capabilities. --- ### 2. Technical Specifications (Typical) Based on the standard nomenclature for this series, here are the likely technical parameters: | Parameter | Estimated Value | Notes | | :--- | :--- | :--- | | **Resistance Value** | 4.7 kΩ (Typical) | Based on the "47" prefix coding. | | **Power Rating** | 25W - 50W | When mounted to a proper heat sink. | | **Tolerance** | ±1% or ±5% | "B" or "D" suffixes often denote precision levels. | | **Construction** | Wirewound | High stability and surge handling. | | **Termination** | Solder Lugs | Designed for manual wiring or ring terminals. | | **Mounting Style** | Chassis Mount | Features bolt holes for secure attachment. | --- ### 3. Part Number Breakdown While manufacturer codes vary slightly, the alphanumeric string generally follows this logic: * **47L**: Represents the base resistance value or series type (High Power Aluminum Housed). * **AC**: Often refers to the physical package size or lead configuration. * **1D2B**: Specific internal codes for tolerance (D=0.5%, B=0.1% in some high-precision contexts) and temperature coefficient. * **-R**: Indicates compliance with **RoHS** (Restriction of Hazardous Substances) standards. --- ### 4. Key Applications * **Dynamic Braking:** Used in motor controllers to dissipate energy. * **Load Testing:** Acts as a dummy load for power supply testing. * **Inrush Current Limiting:** Protects circuits from power spikes during startup. * **Voltage Dividers:** Used in high-power sensing circuits where stability is critical. --- ### 5. Installation Requirements To achieve the rated wattage, the following conditions must be met: 1. **Heat Sink:** Must be mounted on a metal surface (usually aluminum). 2. **Thermal Paste:** A thin layer of thermal compound should be applied between the resistor base and the chassis. 3. **De-rating:** If used in free air (without a heat sink), the power capacity drops to approximately 25-40% of its rated value.