## ESD-R-47D-B: Overview and Technical Specifications The **ESD-R-47D-B** is a high-performance **EMI (Electromagnetic Interference) core** manufactured by KEMET (a YAGEO company). It belongs to the ESD-R series, which consists of round-shaped ferrite cores designed to suppress high-frequency noise in electronic circuits. ### 1. Key Characteristics This component is a **Toroidal (Ring) Ferrite Core** used for EMI/EMC shielding. It is specifically designed to be used with round cables to prevent interference from entering or leaving a system. | Feature | Specification | | :--- | :--- | | **Material** | Manganese-Zinc (Mn-Zn) | | **Shape** | Round (Toroid / Ring) | | **Color** | Black | | **Coating** | Bare (Uncoated) | | **Impedance Type** | High-frequency suppression | --- ### 2. Physical Dimensions The "47D" in the part number corresponds to specific physical sizing (measured in millimeters). | Dimension | Value (mm) | | :--- | :--- | | **Outer Diameter (OD)** | 47.0 mm | | **Inner Diameter (ID)** | 27.0 mm | | **Thickness (H)** | 15.0 mm | --- ### 3. Electronic Functionality The ESD-R-47D-B acts as a **passive low-pass filter**. It works by providing high impedance to high-frequency noise while allowing low-frequency signals (like power or data) to pass through with minimal attenuation. * **Noise Absorption:** It converts high-frequency electromagnetic noise into a negligible amount of heat through magnetic hysteresis and eddy current losses. * **Common Mode Choke:** When a cable is looped through the core, it creates an inductance that suppresses common-mode noise. * **Broadband Performance:** Effective across a wide range of frequencies, typically in the MHz range. --- ### 4. Common Applications * **Power Supplies:** Suppressing switching noise in SMPS (Switched-Mode Power Supplies). * **Industrial Equipment:** Protecting sensitive sensor data from motor interference. * **Consumer Electronics:** Reducing EMI in audio/video cables and computer peripherals. * **Automotive:** Filtering noise in electronic control units (ECUs). --- ### 5. Part Number Breakdown * **ESD-R:** Series name (EMI Cores for Round Cables). * **47:** Refers to the outer diameter size (approx. 47mm). * **D:** Specific height/thickness variation. * **B:** Indicates the specific material composition (Mn-Zn).