## Overview of ESD-R-47H The **ESD-R-47H** is a high-performance **EMI (Electromagnetic Interference) Core** produced by KEMET. It belongs to the ESD-R series of round ferrite cores designed for use on round cables to suppress high-frequency noise. --- ### 1. Key Technical Specifications Below are the primary technical characteristics of the ESD-R-47H: | Feature | Specification | | :--- | :--- | | **Material** | Manganese-Zinc (Mn-Zn) | | **Shape** | Toroidal / Round Core | | **Inner Diameter (ID)** | 27.4 mm | | **Outer Diameter (OD)** | 47.0 mm | | **Height (H)** | 15.0 mm | | **Impedance (at 100 MHz)** | ~115 $\Omega$ (Typical) | | **Operating Temp Range** | -25°C to +85°C | --- ### 2. Electronic Functionality The ESD-R-47H acts as a **passive low-pass filter**. It works by utilizing the magnetic properties of the ferrite material to manage electromagnetic energy: * **Inductive Reactance:** At lower frequencies, the core adds inductance to the wire, resisting changes in current. * **Resistive Loss:** At high frequencies (EMI range), the core's magnetic losses increase. It converts the unwanted high-frequency noise energy into a small amount of heat, effectively removing it from the signal path. * **Common Mode Suppression:** When placed around a bundle of wires (like a power cord), it effectively cancels out common-mode noise that travels in the same direction on all lines. --- ### 3. Application Areas Because of its Manganese-Zinc (Mn-Zn) composition, this specific part is optimized for **lower frequency ranges** (typically under 10 MHz for maximum effectiveness, though it provides impedance up to 100 MHz+). * **Consumer Electronics:** Power supplies for TVs, audio equipment, and white goods. * **Industrial:** Noise suppression for motor controllers and heavy machinery. * **Computing:** Protecting data lines and peripheral cables from interference. --- ### 4. Installation Guidelines To get the best performance out of the ESD-R-47H, follow these electronic design principles: 1. **Placement:** Place the core as close to the noise source or the entry point of the device as possible. 2. **Turns:** Winding the cable through the core multiple times (e.g., 2 or 3 turns) increases the impedance proportionally to the square of the number of turns ($Z \propto N^2$). 3. **Fit:** Ensure the cable diameter is close to the 27.4 mm inner diameter to minimize the air gap, though a loose fit is still functional.