The **B84142-B25-R** is a high-performance **2-line EMC (Electromagnetic Compatibility) Filter** manufactured by TDK Electronics (formerly EPCOS). It is designed to suppress electromagnetic interference (EMI) in single-phase power supply systems. --- ### ## Technical Specifications | Parameter | Specification | | :--- | :--- | | **Manufacturer** | TDK / EPCOS | | **Series** | B84142 | | **Rated Voltage** | 250 V AC/DC (50/60 Hz) | | **Rated Current** | 25 A (at 40°C) | | **Number of Lines** | 2 (Single-Phase) | | **Test Voltage** | 1414 V DC (Line to Line), 2700 V DC (Line to Case) | | **Mounting Type** | Chassis Mount | | **Termination Style** | Threaded Studs / Screw Terminals | --- ### ## Key Electronic Components & Construction The internal circuit of the B84142-B25-R typically follows a **Pi-filter (π)** or a multi-stage LC network topology. It consists of the following electronic parts: 1. **Current-Compensated Chokes (Inductors):** * These are wound on a high-permeability ferrite core. * **Function:** They provide high impedance to common-mode noise (interference occurring on both lines relative to ground) while allowing the power current to pass through. 2. **X2 Capacitors:** * Connected across the line (L) and neutral (N). * **Function:** They suppress differential-mode noise (interference between the two lines). 3. **Y2 Capacitors:** * Connected between the lines and the metal housing (ground). * **Function:** They shunt high-frequency common-mode noise to the ground. These are safety-rated to ensure low leakage current. 4. **Discharge Resistor:** * Often integrated across the X2 capacitors. * **Function:** Safely discharges the energy stored in the capacitors once power is disconnected to prevent electric shock. --- ### ## Applications This specific filter is commonly found in industrial electronics where high current and reliability are required: * **Variable Speed Drives (VSDs):** Reducing switching noise from motor controllers. * **Power Supplies:** Switched-mode power supplies (SMPS) for industrial PCs. * **Medical Equipment:** Ensuring low electromagnetic emissions in sensitive environments. * **Automation:** Protecting PLC systems from grid disturbances. --- ### ## Mechanical & Safety Features * **Housing:** Compact metal case providing excellent internal shielding. * **Climatic Category:** IEC 60068-1 (25/100/21), meaning it operates from -25°C to +100°C. * **Compliance:** UL/CSA and ENEC approvals for global safety standards.