The **ESD-R-31SR** is a high-performance, snap-on EMI (Electromagnetic Interference) suppression core manufactured by **KEMET**. It belongs to the ESD-R series, specifically designed for use on round cables to mitigate high-frequency noise. --- ### 1. Key Technical Specifications The "SR" designation typically indicates a "snap-on" or "split" ferrite design, allowing for easy installation on existing wiring. | Parameter | Specification | | :--- | :--- | | **Core Shape** | Round, Split (Snap-on) | | **Material** | Manganese-Zinc (Mn-Zn) or Nickel-Zinc (Ni-Zn) | | **Outer Diameter (OD)** | ~31 mm | | **Application** | Noise suppression for round cables | | **Mounting Type** | Snap-on (with plastic housing) | | **Operating Temperature** | -25°C to +85°C | --- ### 2. Physical Structure & Components The ESD-R-31SR consists of three primary components: 1. **Ferrite Core:** Two halves of sintered magnetic material (ferrite) that form a complete circle when closed. 2. **Plastic Case:** A UL94 V-0 flame-retardant nylon housing that holds the ferrite halves. 3. **Locking Mechanism:** A snap-lock system that ensures the core remains tightly clamped around the cable without sliding. --- ### 3. Electronic Functionality The part acts as a **Common Mode Choke** (passive low-pass filter). It works by: * **Increasing Impedance:** When wrapped around a cable, it provides high impedance to high-frequency electromagnetic noise. * **Heat Dissipation:** It absorbs EMI energy and converts it into a negligible amount of heat, preventing it from interfering with sensitive electronics. * **Non-Invasive Filtering:** Because it is a "snap-on" part, it does not require cutting the wire or modifying the circuit board. --- ### 4. Typical Applications The ESD-R-31SR is commonly found in environments where signal integrity is critical: * **Consumer Electronics:** PC power cords, monitor cables, and printer cables. * **Industrial Equipment:** Control panels and motor drive wiring. * **Telecommunications:** Data transmission lines to prevent crosstalk and RF interference. * **Medical Devices:** Ensuring sensitive diagnostic tools are not affected by ambient electrical noise. --- ### 5. Installation Note To maximize the effectiveness of the ESD-R-31SR, the cable should be looped through the core multiple times if the cable diameter allows. Each turn increases the effective impedance significantly: * **1 Turn:** Standard suppression. * **2 Turns:** Impedance increases by approximately 4x.