1. Introduction
This manual provides essential information for the proper use and handling of EE32, EE33, and EI33 series transformer ferrite magnetic cores and their corresponding coil former bobbins. These components are designed for use in various electronic applications, particularly in the construction of transformers and inductors for power conversion, filtering, and signal processing. The cores are made from PC40 Mn-Zn power ferrite material, optimized for high-frequency performance.
2. Safety Information
- Always ensure power is disconnected from any circuit before installing or modifying components.
- Installation should ideally be performed by qualified personnel familiar with electronic circuit assembly.
- Ferrite cores are ceramic materials and can be brittle. Handle with care to prevent chipping or breakage.
- Avoid touching live electrical circuits.
- Keep components away from moisture and extreme temperatures.
3. Product Overview
The product consists of two main parts: the ferrite magnetic core and the coil former (bobbin). The ferrite core provides a path for magnetic flux, while the bobbin provides a structure for winding copper wire to form coils. These components are crucial for building custom transformers and inductors.
Figure 1: Overview of EE33 and EI33 ferrite cores and bobbins with different pin configurations.
Figure 2: Example of a bobbin and core assembly.
4. Specifications
4.1 General Properties
| Characteristic | Value |
|---|---|
| Customized | Yes |
| Coil Structure | Other |
| Coil Number | Other |
| Phase | Other |
| Origin | Mainland China |
| Certification | None |
| Use | Other |
4.2 Material Characteristics (PC40 Power Ferrite)
Figure 3: PC40 Power Ferrite Material Characteristics Table.
Note: The values were obtained with a toroidal core Φ25×Φ15×10 at room temperature unless otherwise specified. Typical values are based on test conditions of f=400kHz, B=50mT, and f=500kHz, B=30mT.
4.3 Dimensions (EE/EI Types)
Figure 4: Dimensions (in mm) for various EE and EI core types. Refer to the diagram in the image for dimension labels A-F.
4.4 Inductance Factor (AL)
Figure 5: Inductance Factor (AL) values (nH/N²) for various EE and EI core types at AL: 250mV, 100T.
4.5 Bobbin Pin Configuration
Figure 6: Vertical bobbin showing pin pitch and array pitch. For the 18+18 Pins bobbin, the Pin Pitch is 2.5mm and Array Pitch is 23mm.
5. Setup and Installation
The assembly of the ferrite core and bobbin is a straightforward process, but care must be taken to ensure proper fit and avoid damage.
5.1 Core and Bobbin Assembly
- Carefully align the two halves of the ferrite core with the central opening of the bobbin.
- Gently press the core halves into the bobbin until they fit snugly. Ensure there are no gaps between the core halves if a gapless design is intended, or ensure the intended gap is maintained if an air gap is part of the design.
- Avoid excessive force, which can crack the ferrite material or damage the bobbin.
5.2 Coil Winding
Once the core and bobbin are assembled, wire can be wound around the bobbin to create the primary and secondary coils. The number of turns, wire gauge, and winding technique will depend on the specific electrical design requirements (e.g., desired inductance, voltage transformation ratio, current capacity).
- Ensure the wire is insulated to prevent short circuits between turns or layers.
- Distribute windings evenly to optimize performance and minimize parasitic effects.
- Secure the ends of the windings to the bobbin pins, typically by soldering.
5.3 Mounting
The assembled transformer/inductor can be mounted onto a PCB or chassis using the bobbin's pins or other mounting features. Ensure secure mounting to prevent vibration or mechanical stress.
6. Operating Principles
Ferrite magnetic cores are essential components in high-frequency power electronics and signal processing. Their high magnetic permeability allows them to concentrate magnetic flux efficiently, while their high electrical resistivity minimizes eddy current losses at high frequencies. The Mn-Zn PC40 material is specifically chosen for its low power loss characteristics, making it suitable for power applications.
When current flows through a coil wound on the bobbin, it generates a magnetic field within the ferrite core. This magnetic field induces a voltage in other coils wound on the same core (transformer action) or stores energy (inductor action). The efficiency and performance of the component are highly dependent on the core material, its geometry, and the winding design.
7. Maintenance
- Keep the components clean and free from dust and debris.
- Store unused cores and bobbins in a dry environment at room temperature to prevent material degradation.
- Periodically inspect assembled units for any signs of physical damage, such as cracks in the ferrite core or damaged bobbin pins.
- Avoid exposing the components to strong mechanical shocks or vibrations.
8. Troubleshooting
As these are component parts, troubleshooting typically involves verifying the correct assembly and integration into a larger circuit.
- No Inductance/Incorrect Inductance: Verify the number of turns, wire gauge, and ensure the core halves are properly seated without unintended gaps. Check for shorted turns in the winding.
- Overheating: This could indicate excessive current, incorrect core material for the operating frequency/power, or insufficient wire gauge. Re-evaluate the design parameters.
- Physical Damage: If the ferrite core is cracked or chipped, its magnetic properties will be compromised, and it should be replaced.
- Poor Electrical Connection: Ensure all wire ends are securely soldered to the bobbin pins and that the pins make good contact with the PCB.
9. User Tips
- Always refer to the detailed specifications (dimensions, material characteristics, AL values) to ensure the chosen core and bobbin are appropriate for your specific application's frequency, power, and physical constraints.
- For critical applications, consider performing a small batch of tests to validate performance before full-scale production.
10. Warranty and Support
For technical assistance, questions regarding product specifications, or in case of any issues with the components, please contact the seller directly. Provide your purchase details and a clear description of the issue to facilitate prompt support.
