Size marking on the case is the bare core dimension (OD × ID × H), not the cased or finished size.
Nanocrystalline toroidal core 12×8×4.5 mm
12×8×4.5 mm nanocrystalline toroidal core, Black PBT Class B 130C.
Soft-published ahead of stock. Expected availability October 20, 2026. The image is a dimension diagram; product photos will be added when inventory arrives.
CCNT-012-008-004P5-HFBK is a 12×8×4.5 mm nanocrystalline toroidal core for small-signal EMI chokes, USB/phone charger filters, and low-power SMPS output chokes. Its nanocrystalline HF characteristic supports common-mode and EMI filter designs where impedance and winding window matter as much as size. Choose this size when the filter or choke needs this window and OD, not the next larger footprint.
Arriving October 20, 2026
$0.841 piece
This SKU is soft-published for selection and SEO. Product photos will be added when stock arrives. Request a quote now, or join the waitlist for an in-stock notice.
Technical Specifications
Bare core dimensions
Cased / finished dimensions
Magnetic properties
Finish and handling
Environmental
Applications and selection
Applications
- small-signal EMI chokes
- USB/phone charger filters
- low-power SMPS output chokes
- pulse transformers
- sub-5W SMPS common-mode EMI filter chokes
- USB power adapter differential/common-mode filters
- small-signal pulse transformers
- low-power flyback auxiliary windings
- signal isolation transformers
When to choose this size
This 12×8×4.5 mm toroidal core is sized for small-signal EMI chokes and related designs in the nearby size family. This is the compact end of the nearby size family: use it when the design is limited by board space or a small magnetic footprint. Move up to the 13×9.5×5 mm core when you need a larger outer diameter, winding window, or higher throughput than this part can comfortably support. In short, pick CCNT-012-008-004P5-HFBK when your design for small-signal EMI chokes fits this window and OD; pick a neighbor when compactness or power handling shifts the trade-off.
Winding notes
Magnetic calculations should use the bare 12×8×4.5 mm geometry (Ae 0.07 cm², Le 3.1 cm). The winding must fit the finished window: cased ID is 6.6 mm, not the 8 mm bare ID. Distribute common-mode windings evenly and keep leakage paths short for EMI filter performance. High permeability (μi 80,000) supports useful magnetizing inductance at practical turn counts; stay within 1.25 Tesla saturation and the -40°C to +130°C PBT Class B 130C limit.
Related application guides
Frequently asked questions
Are stated dimensions bare or cased?
The 12×8×4.5 mm size marked on the case is the bare core (OD × ID × H). Finished cased size is 14.3 × 6.6 × 7 mm. Use bare dimensions with Ae and Le for magnetic design, and the finished inner diameter for winding clearance.
Is this core suitable for EMI or common-mode filter work?
Yes. It is a nanocrystalline toroidal core commonly used for small-signal EMI chokes, including sub-5W SMPS common-mode EMI filter chokes. Size the turns and window for your common-mode impedance target while staying within saturation and temperature limits.
When should I choose a different size instead?
Choose the 13×9.5×5 mm core when you need a larger winding window, heavier magnet wire, more turns, or higher throughput than this 12×8×4.5 mm core provides.
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