The **ESD-R-47B** is a high-performance EMI/RFI suppression component, specifically a **round ferrite core** designed for use on round cables. It is manufactured by **KEMET** (a subsidiary of YAGEO). --- ### 1. Technical Specifications The ESD-R-47B is part of the ESD-R series, which uses manganese-zinc (Mn-Zn) or nickel-zinc (Ni-Zn) ferrite materials to attenuate high-frequency noise. | Parameter | Specification | | :--- | :--- | | **Material Type** | Ni-Zn (Nickel-Zinc) | | **Outer Diameter (OD)** | 47.0 mm | | **Inner Diameter (ID)** | 27.0 mm | | **Height (H)** | 15.0 mm | | **Operating Temperature** | -25°C to +85°C | | **Primary Function** | EMI/RFI Suppression | | **Color** | Grey (Bare Ferrite) | --- ### 2. Core Working Principles The ESD-R-47B functions as a **passive low-pass filter**. It works through two primary mechanisms: 1. **Impedance Induction:** At high frequencies (the MHz range), the ferrite core acts as a high-impedance resistor. 2. **Heat Dissipation:** It absorbs unwanted electromagnetic interference (EMI) and dissipates it as a negligible amount of heat, rather than reflecting it back into the system. ### 3. Key Features & Applications The "B" suffix in the part number usually indicates specific material properties or dimensions within the KEMET catalog tailored for broad frequency coverage. #### Features * **Broadband Suppression:** Effective across a wide range of frequencies, particularly in the FM band and higher. * **Solid Construction:** This is a "toroidal" or ring core, meaning the cable must be threaded through it during assembly (as opposed to "snap-on" cores). * **Compliance:** Usually RoHS and REACH compliant. #### Common Applications * **Industrial Equipment:** Reducing noise in motor controllers and heavy machinery. * **Consumer Electronics:** Filtering power cords for large appliances. * **Data Lines:** Protecting signal integrity in telecommunications cabling. * **Power Supplies:** Suppressing switching noise from SMPS (Switched-Mode Power Supplies). --- ### 4. Installation Example To achieve maximum impedance, multiple turns of the wire can sometimes be looped through the core. ```python # Theoretical Impedance Calculation (Simplified) # Impedance (Z) is proportional to the square of the number of turns (N) # Z ∝ N² def calculate_impedance(base_impedance, turns): return base_impedance * (turns ** 2) print(f"Impedance with 2 turns: {calculate_impedance(100, 2)} Ohms") ```