The **ESD-R-25S** is a specialized electronic component categorized as an **EMI Core** or **Ferrite Core**. It is primarily used to suppress electromagnetic interference (EMI) and noise in electronic circuits. ### 1. Component Overview The ESD-R-25S belongs to the **ESD-R Series** manufactured by KEMET (a YAGEO company). These are round, solid (toroidal) ferrite cores designed for use on round cables to attenuate high-frequency noise. --- ### 2. Technical Specifications | Parameter | Specification | | :--- | :--- | | **Material** | Manganese-Zinc (Mn-Zn) | | **Shape** | Round / Toroidal (Solid) | | **Outer Diameter (OD)** | 25.0 mm | | **Inner Diameter (ID)** | 15.0 mm | | **Thickness (H)** | 12.0 mm | | **Frequency Range** | High-frequency (typically MHz range) | | **Operating Temp** | -25°C to +85°C | --- ### 3. Key Electronic Functions The part acts as a **passive low-pass filter** when a cable is passed through its center. * **Impedance Generation:** It introduces high impedance at high frequencies while remaining transparent to DC or low-frequency signals. * **Common Mode Choke:** When multiple conductors pass through the core, it suppresses common-mode noise without affecting differential-mode signals. * **Energy Dissipation:** It converts unwanted high-frequency electromagnetic energy into a negligible amount of heat through magnetic hysteresis and eddy currents. --- ### 4. Typical Applications The ESD-R-25S is used in various industries to ensure compliance with EMC (Electromagnetic Compatibility) standards: * **Consumer Electronics:** Televisions, gaming consoles, and audio equipment. * **Industrial:** Power supplies and motor controllers. * **Computing:** Peripheral cables (USB, HDMI) and internal power wiring. --- ### 5. Installation Note To use this part effectively, cables are typically threaded through the core. For increased noise suppression, the cable can be looped through the core multiple times, which increases the effective impedance by the square of the number of turns ($Z \propto N^2$).