The **ESD-R-25D** is a high-performance toroidal EMI core manufactured by **KEMET**. It is specifically designed to suppress electromagnetic interference (EMI) in electrical circuits by acting as a high-frequency filter. --- ## 1. Core Specifications and Physical Properties The ESD-R-25D belongs to the **ESD-R series**, which features a round (toroidal) shape designed to have cables or wires looped through the center. | Feature | Specification | | :--- | :--- | | **Material** | Manganese-Zinc (Mn-Zn) Ferrite | | **Outer Diameter (OD)** | 25.0 mm | | **Inner Diameter (ID)** | 15.0 mm | | **Height (H)** | 12.0 mm | | **Operating Temp Range** | -25°C to +85°C | | **Primary Function** | High-frequency noise suppression | --- ## 2. Technical Characteristics The performance of the ESD-R-25D is defined by its impedance characteristics and the material type. ### Material Selection (Mn-Zn) The "D" suffix often denotes the specific material composition. Mn-Zn ferrite is generally optimized for **lower frequency ranges** (under 10 MHz) compared to Ni-Zn (Nickel-Zinc) ferrites, though it remains effective across a broad spectrum for general EMI cleanup. ### Key Benefits * **Broadband Suppression:** Effective at reducing conducted noise in signal and power lines. * **Simple Integration:** Does not require soldering; wires are simply passed through the core. * **Impedance Boost:** Winding the wire through the core multiple times ($N$ turns) increases the impedance by $N^2$. --- ## 3. Common Applications The ESD-R-25D is used in environments where electronic components might interfere with each other or where external signals could disrupt sensitive equipment: 1. **Consumer Electronics:** Power cords for TVs, laptops, and gaming consoles. 2. **Industrial Machinery:** Protecting control signals from high-power motor noise. 3. **Medical Equipment:** Ensuring signal integrity in diagnostic devices. 4. **Power Supplies:** Filtering the input/output of Switched-Mode Power Supplies (SMPS). --- ## 4. Usage Example To implement the ESD-R-25D in a circuit, a designer typically follows these steps: ```markdown 1. Identify the cable carrying the noise (e.g., a DC power line). 2. Pass the cable through the center of the ESD-R-25D. 3. For higher impedance, loop the cable through a second or third time. 4. Secure the core using a cable tie or heat-shrink tubing if necessary. ``` ---