线路滤波器（共模电感Common mode Choke)，也叫共模扼流圈，是将两个线圈绕在同一铁芯上，匝数和相位都相同(绕制反向)。这样，当电路中的正常电流流经共模电感时，电流在同相位绕制的电感线圈中产生反向的磁场而相互抵消，此时正常信号电流主要受线圈电阻的影响(和少量因漏感造成的阻尼)；当有共模电流流经线圈时，由于共模电流的同向性，会在线圈内产生同向的磁场而增大线圈的感抗，使线圈表现为高阻抗，产生较强的阻尼效果，以此衰减共模电流，达到滤波的目的。
锰锌共模电感用高导磁芯，具有较高的初始磁导率，较高的饱和磁感应强度，在1KHz-1MHz频段具有优良的磁性能。在交流下磁导率为复数磁导率，共模电感利用其阻抗特性，所以适用频率可以远高于磁芯的截止频率。
线路滤波器均符合ROHS规范，Lead-Free无铅标准，提供完整线圈电感器尺寸，感量范围齐全，可依客户的需求制造。
Line filters, also known as Common Mode Chokes (CMC), consist of two coils wound onto a single magnetic core with the identical number of turns and phase (wound in opposite directions). When normal differential-mode current flows through the choke, the currents generate opposing magnetic fields in the coils that effectively cancel each other out. As a result, the normal signal current is primarily influenced only by the DC resistance of the wire and minor damping caused by leakage inductance. Conversely, when common-mode current flows through the coils, its identical direction generates additive magnetic fields that significantly increase the inductive reactance. This creates high impedance and a powerful damping effect, which attenuates the common-mode current to achieve the desired filtering objective.
Mn-Zn (Manganese-Zinc) common mode chokes utilize high-permeability cores characterized by high initial permeability and high saturation induction strength, delivering excellent magnetic performance within the 1KHz to 1MHz frequency band. Under alternating current (AC) conditions, the material exhibits complex permeability. By leveraging these impedance characteristics, common mode chokes can operate at frequencies far exceeding the core’s magnetic cutoff frequency. All our line filters are fully compliant with RoHS and Lead-Free standards. We provide a comprehensive range of dimensions and inductance values, and we offer full customization services to meet specific customer requirements.
料号标识P/N Identification
①LF：线路滤波器。
LF：Line Filter.
②△=B=Boboin，LFBV外壳共模电感; △=D=底座或底板，LFDV带底座/底板共模电感。
△=B=Boboin，LFBV Series Cased Common Mode Inductor； △=D=Case / Housing，LFDV Series Common Mode Inductor with Base.
③出线脚形状：V立式，H卧式。
Terminal/Lead Configuration: V for Vertical, H for Horizontal.
④磁芯规格：外径X内径X高。
Core Dimensions: OD x ID x HT.
⑤电感值：例如"102"代表1000 uH。
Inductance: e.g., "102" represents 1,000μH.
⑥电感值容许公差:"N":+30%; "U":最小值。
Inductance Tolerance: "N" denotes ±30%; "U" denotes Minimum (Min.).
⑦线径。
Wire Diameter.
产品特点Product Features1. 线路滤波器抑制各种电子设备电源电路产生的低频至高频传导噪声。
Effective Noise Suppression: These line filters suppress conducted noise across a wide spectrum, from low to high frequencies, generated by the power circuits of various electronic equipment.
2. 高安全性和可靠性。
High Safety and Reliability: Designed to ensure maximum safety and long-term operational reliability.
3. 可以垂直和水平安装，以优化PCB板布局。
Flexible Mounting Options: Available in both vertical and horizontal mounting configurations to optimize PCB layout and space utilization.
4. 可以方便的通过选取不同磁导率磁芯、不同圈数、不同绕线方式等来达到所需阻抗值和适用频带。
Highly Customizable Impedance: Desired impedance values and target frequency bands can be easily achieved by selecting different core permeabilities, adjusting the number of turns, or employing various winding techniques.
测试设备及条件Test Equipment & Conditions1. L: TH2828S Automatic Component Analyzer
2. SRF: HP4291B RF Impedance/Material Analyzer
3. DCR: TH2513A Milli-ohm meter
4. Electrical specifications at 25℃
5. Test Condition：1KHz/0.25Vrms
锰锌磁环磁导率与频率关系Permeability vs. Frequency Characteristics (Mn-Zn)选择与频带相匹配的铁氧体磁芯是最有效的降噪措施，铁氧体材料根据其磁导率有对应的有效频带，关于各材质对应的频带范围关系图如本页图示。 磁导率越高对低频带噪声滤除越有效，磁导率越低对高频带噪声滤除越有效，锰锌磁环大部分情况运用在传导噪声对策上。图中所示的频带范围只是一个大致范围，因为实际的共模电感抑制噪声范围还受磁芯形状、尺寸、绕线圈数、绕线方式、线材、交变电流复数磁导率等诸多因素影响。所以为了能准确的判断共模电感抑制噪声范围需进行实际的测试确定。由于各磁性材料厂家生产的磁芯品质不一，相同磁导率的磁芯也许频率特性不一样，也许居里温度不一样，也许损耗不一样，也许抗偏直电流特性不一样。
Selecting a ferrite core that matches the target frequency band is the most effective measure for noise reduction as each ferrite material has a specific effective frequency range based on its permeability, as illustrated in the characteristic chart on this page. Generally, higher permeability is more effective for filtering low-frequency noise while lower permeability provides better results for high-frequency noise, with Mn-Zn toroidal cores being predominantly utilized for conducted noise suppression. However, the frequency ranges shown in the chart are only approximate because the actual noise suppression spectrum of a common mode choke is influenced by numerous factors such as core geometry, dimensions, number of turns, winding techniques, wire type, and the complex permeability under alternating current. Therefore, empirical testing is essential to accurately determine the effective suppression range. Furthermore, due to varying quality among magnetic material manufacturers, cores with the identical nominal permeability may exhibit different frequency characteristics, Curie temperatures, power losses, or DC bias performance.
共模电感部分产品图示Typical Product Illustrations - Common Mode Chokes
