The **SS21V-R050540** is a common mode choke coil (inductor) primarily used for noise suppression in power supply circuits. It belongs to the SS series manufactured by **KEMET** (formerly Tokin). --- ## 1. Technical Specifications The part number encodes specific electrical characteristics. Here is the breakdown of its technical profile: | Parameter | Value / Specification | | :--- | :--- | | **Inductance (Min)** | 54.0 mH | | **Rated Current (AC)** | 0.5 A | | **DC Resistance (Max)** | 1.80 Ω | | **Temperature Rise (Max)** | 45 K | | **Operating Temp Range** | -25°C to +120°C | | **Voltage Rating** | 250 VAC | --- ## 2. Part Number Breakdown Understanding the nomenclature helps identify its physical and electrical properties: * **SS**: Series name (Standard type common mode choke). * **21**: Size code (Physical dimensions of the core/base). * **V**: Terminal orientation (Vertical type). * **R**: High-permeability ferrite material. * **05**: Rated current (0.5 Amperes). * **0540**: Nominal Inductance (54.0 mH). --- ## 3. Key Electronic Functions The SS21V-R050540 serves three primary roles in an electronic circuit: ### A. Common Mode Noise Suppression It is designed to filter out electromagnetic interference (EMI) that travels in the same direction on both power lines (Common Mode). It allows the "Differential Mode" (the actual power signal) to pass through with minimal impedance. ### B. High Inductance at Low Current With a high inductance of **54 mH**, this specific model is highly effective at filtering lower frequency noise. However, because it is rated for **0.5A**, it is intended for low-power applications. ### C. Magnetic Core Technology The "R" designation indicates the use of high-permeability manganese-zinc (Mn-Zn) ferrite cores. This provides high impedance in a compact vertical footprint, saving PCB real estate. --- ## 4. Typical Applications * **Switching Power Supplies (SMPS):** Used at the AC input stage to prevent noise from leaking back into the grid. * **LED Lighting:** Suppressing flicker and noise in LED drivers. * **Consumer Electronics:** Power boards for TVs, audio equipment, and office automation. * **Adapters:** Compact AC/DC chargers for portable devices. ---