In modern power systems, common-mode and differential-mode noise exist simultaneously in AC mains filters and DC chokes for SMPS applications. A toroidal CMC suppresses common-mode noise through magnetic flux confined inside a high-permeability core. Compared to using multiple single power inductors, a single toroidal CMC offers better noise attenuation, smaller size, lower cost, and less waveform distortion even under large differential currents. Coilmaster provides a wide range of through-hole toroidal chokes—from compact CMT1205B (15×7.5×18mm) up to CMT3615B (45.72×24.9×45.72mm). Customized designs are fully supported, including core selection, winding scheme, insulation rating, and mechanical form factor.

Advantage of Through-Hole Common Mode Choke

Through-hole common mode chokes typically use MnZn or high-μ materials to achieve high inductance and strong impedance, delivering superior noise suppression even in demanding power applications. The two-section bobbin and single-layer winding reduce stray capacitance, enabling excellent high-frequency characteristics—including FM band suppression. They offer higher isolation voltage (Hi-Pot), strong mechanical strength, and cost-effective EMI filtering for power supply lines and industrial equipment.

Why Toroidal Filters Perform Better

Characteristic

High inductance and impedance
Low stray capacitance
High μ MnZn core
Excellent high-frequency suppression
Two-section bobbin structure
Wide size range
High isolation capability

Features

• Effective high-frequency noise suppression.
• Stable differential-mode current handling.
• High common-mode impedance.
• Strong mechanical durability for high-power circuits.
• Cost-effective EMI filtering.
• Lower waveform distortion vs. multiple single inductors.

Applications

• AC mains filters
• SMPS input filtering
• Industrial controllers and motor drives
• Inverters and power conversion systems
• Measuring equipment and instrumentation
• RFI/EMI suppression for high-voltage or high-power lines