Circular inductors are widely used in power filtering, signal processing, power conversion, and other scenarios due to the unique electromagnetic characteristics brought by the circular magnetic core structure, The advantage of a circular inductor lies in its closed magnetic circuit design (the magnetic core is circular and the winding is evenly wound around the outer circumference). Compared with traditional I-shaped inductors and surface mount inductors, it has significant differences in magnetic efficiency, loss control, and space utilization: 1. High magnetic efficiency, small leakage magnetic pole Magnetic circuit closure without air gap: The magnetic circuit of the annular magnetic core is completely closed (without the “core gap” of traditional inductors), and the magnetic field lines are almost entirely confined inside the core. The leakage coefficient is usually less than 5% (the leakage coefficient of traditional I-shaped inductors can reach 20% -30%), greatly reducing electromagnetic interference (EMI) to surrounding circuits. Example: In a switching power supply, the leakage magnetic interference of a ring inductor is 15-20dB lower than that of an I-shaped inductor of the same power, which can reduce signal interference to peripheral chips (such as MCU). 2. Low power loss and excellent efficiency (both copper loss and iron loss are low) The winding is uniformly wound around the annular magnetic core, with shorter wire length (reduced by 10% -15% compared to resonant inductance), lower DC resistance, and significantly reduced copper loss. The magnetic core uses high-frequency low loss materials (such as iron silicon aluminum, nanocrystals, and high-frequency ferrite), and in the high frequency range of 10kHz-1MHz, the iron loss (hysteresis loss+eddy current loss) is 20% -30% lower than traditional magnetic cores. 3. High power density and compact size At the same power/inductance value, the volume of a circular inductor is reduced by 20% -40% and the weight is reduced by 30% -50% compared to traditional inductors. 4. Stable parameters and strong anti-interference ability Good linearity of inductance: Within 1.5 times the rated current range, the inductance deviation is usually less than ± 5% (traditional inductors may reach ± 10%), especially suitable for filtering scenarios that require high inductance accuracy (such as DC side smoothing of photovoltaic inverters). Excellent vibration resistance and temperature stability: The annular structure has no risk of “magnetic core loosening”, and the working temperature range is wide (-55 ℃~+125 ℃, some industrial grade can reach+155 ℃) 5. Flexible design, adaptable to multiple scenarios It can be customized by adjusting the magnetic core material (iron powder core → iron silicon aluminum → nanocrystals, adapted to different frequency/loss requirements), winding wire diameter (0.1mm-2.0mm, matched with 0.1A-50A current), and number of turns (10-1000 turns, achieving 1nH-10mH inductance), supporting single winding (differential mode) and dual winding (common mode) designs, while also considering various functions such as differential mode filtering, common mode suppression, and energy storage.