High-Quality High-Frequency Transformer Core EFD31 Mn-Zn Soft Magnetic Power Ferrite Core
I. Advantages
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High Magnetic Permeability
- EFD Mn-Zn power ferrite cores possess high magnetic permeability, which enhances the efficiency and performance of devices. Under high-frequency and high flux density conditions, their permeability remains high, reducing energy losses and improving operational efficiency.
- High permeability allows the core to store more magnetic energy in a smaller volume, facilitating the miniaturization and lightweighting of electronic devices.
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Low Loss
- These cores exhibit low loss, maintaining good performance at high frequencies. In applications such as switch-mode power supplies, low loss characteristics improve conversion efficiency and stability, reducing energy wastage.
- Low loss also means less heat generation under the same operating conditions, enhancing device reliability and lifespan.
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Good Thermal Stability
- EFD Mn-Zn power ferrite cores have excellent thermal stability, retaining consistent magnetic properties over a wide temperature range. This reliability under various environmental conditions minimizes the impact of temperature changes.
- Good thermal stability also reduces magnetic performance fluctuations due to temperature variations, improving device stability and accuracy.
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Excellent Anti-Interference Capability
- Due to their high magnetic permeability, EFD Mn-Zn power ferrite cores effectively shield against external magnetic fields, preventing interference with circuits. This is crucial for enhancing the anti-interference ability and electromagnetic compatibility (EMC) of electronic devices.
- Effective anti-interference capability ensures proper operation in complex electromagnetic environments, reducing faults and errors caused by interference.
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Easy Installation and Processing
- EFD Mn-Zn power ferrite cores typically come in regular shapes and sizes, making them easy to install and fix on circuit boards. Their good processability allows customization and processing according to different application needs.
- Easy installation and processing boost production efficiency, reduce costs, and facilitate maintenance and repair.



Fig.1 Fig.2 Fig.3

Fig.4 Fig. 5
| Specification | Figure | Dimension(mm) | Effective parameter | Inductor coefficient AL(nH/N2) | Weight (grams/pair) | |||||||||
| A | B | C | D1 | D2 | E | F | Ae(mm2) | Le(mm) | Ve(mm3) | BP44 | BP95 | |||
| EFD15.5/8/5 | 1 | 15.5±0.4 | 7.75±0.2 | 4.65±0.15 | 5.3±0.20 | 2.4±0.15 | 11.0min | 5.7±0.2 | 14.50 | 35.40 | 513.80 | 950±25% | 1150±25% | 3.50 |
| EFD16/8/5 | 3 | 16.35±0.3 | 7.6±0.2 | 4.8±0.2 | 6.0±0.15 | 2.5±0.15 | 12.4min | 5.4±0.2 | 16.90 | 36.10 | 608.70 | 1000±25% | 1200±25% | 3.80 |
| EFD17/8/6 | 3 | 17.00±0.3 | 8.15±0.15 | 5.60±0.2 | 6.0±0.20 | 3.3±0.20 | 12.5min | 5.55±0.2 | 22.70 | 37.40 | 849.10 | 1500±25% | 1750±25% | 5.45 |
| EFD18/9/6 | 3 | 17.8±0.3 | 8.60±0.2 | 6.10±0.2 | 7.45±0.15 | 3.4±0.10 | 12.8min | 6.25±0.15 | 27.50 | 39.70 | 1094.00 | 1600±25% | 1800±25% | 6.40 |
| EFD20.3/8/7 | 2 | 20.6±0.35 | 7.60±0.20 | 6.50±0.20 | 8.00±0.20 | 4.7±0.2 | 14.6min | 4.40±0.20 | 37.55 | 35.90 | 1348.05 | 2650±25% | 3300±25% | 7.86 |
| EFD20.6/10/7 | 2 | 20.6±0.40 | 10.0±0.25 | 6.65±0.20 | 8.80±0.20 | 3.6±0.2 | 15.7min | 7.7±0.25 | 29.60 | 48.20 | 1426.00 | 1360±25% | 1500±25% | 8.70 |
| EFD20.8/12/5 | 5 | 20.8±0.35 | 12.1±0.15 | 4.50±0.20 | 8.40±0.20 | 2.95±0.15 | 15.0±0.3 | 9.20±0.15 | 23.90 | 52.10 | 1245.00 | 970±25% | 1150±25% | 8.50 |
| EFD21/10/7 | 2 | 21.0±0.50 | 10.0±0.25 | 6.65±0.20 | 8.65±0.20 | 3.5±0.2 | 16.3min | 7.7±0.25 | 29.60 | 48.50 | 1437.60 | 1360±25% | 1500±25% | 8.70 |
| EFD25/13/9 | 2 | 25.0±0.65 | 12.5±0.25 | 9.1±0.2 | 11.3±0.20 | 5.1±0.2 | 19.0min | 9.4±0.25 | 53.00 | 58.60 | 3105.80 | 2150±25% | 2700±25% | 17.20 |
| EFD25.5/13/9A | 2 | 25.5±0.65 | 12.6±0.25 | 9.1±0.2 | 11.4±0.20 | 5.2±0.2 | 19.4±0.6 | 9.5±0.25 | 55.10 | 59.20 | 3264.00 | 2150±25% | 2700±25% | 18.60 |
| EFD31/15/9 | 2 | 31.4±0.60 | 15.2±0.20 | 9.1±0.2 | 14.6±0.25 | 4.7±0.2 | 23.8 min | 11.4±0.25 | 63.80 | 71.50 | 4562.50 | 2300±25% | 2900±25% | 26.60 |
| EFD35/22/6.5 | 3 | 35.7±0.70 | 21.70±0.20 | 6.50±0.2 | 16.5±0.25 | 3.9±0.2 | 25.5 min | 16.70±0.20 | 64.00 | 95.50 | 6112.00 | 1800±25% | 2300±25% | 41.60 |
| EFD36/24/10 | 3 | 36.2±0.5 | 23.6±0.3 | 10.0±0.3 | 14.0±0.30 | 5.0±0.2 | 25.8 min | 18.7±0.25 | 82.20 | 103.70 | 8530.00 | 2100±25% | 2600±25% | 52.60 |
| EFD38/18/7.6 | 3 | 37.7±0.65 | 17.6±0.25 | 7.60±0.25 | 18.65±0.25 | 3.4±0.2 | 29.4 min | 13.1±0.25 | 61.85 | 81.70 | 5053.15 | 2100±25% | 2500±25% | 34.60 |
| EFD38/19/8-1 | 3 | 38.50±0.65 | 19.40±0.20 | 8.00±0.25 | 18.00±0.25 | 5.0±0.2 | 27.20 min | 13.8±0.25 | 87.80 | 86.30 | 7577.20 | 2400±25% | 2800±25% | 42.80 |
| EFD40/22/8 | 3 | 40.0±0.8 | 22.2±0.3 | 8.0±0.3 | 19.9±0.30 | 4.0±0.2 | 29.5 min | 17.2±0.30 | 78.90 | 100.20 | 7905.00 | 2200±25% | 2500±25% | 49.10 |
| EFD43/17/7 | 3 | 42.6±0.6 | 16.95±0.3 | 7.2±0.3 | 23.0±0.30 | 4.1±0.2 | 28.4 min | 9.55±0.30 | 99.85 | 70.46 | 7036.90 | 3850±25% | 4500±25% | 42.70 |
| EFD45/25/8 | 3 | 45.4±0.6 | 24.90±0.2 | 7.65±0.20 | 23.8±0.20 | 4.0±0.2 | 33.2 min | 18.3±0.25 | 93.60 | 108.80 | 10181.0 | 2400±25% | 2800±25% | 63.70 |
| EFD50/25/8 | 3 | 50.5±0.7 | 25.90±0.3 | 8.8±0.20 | 23.5±0.30 | 5.0±0.2 | 37.6 min | 18.9±0.30 | 114.50 | 116.60 | 13350.7 | 3000±25% | 3600±25% | 83.60 |
Note:
The test conditions for AL value are: 1KHz, 0.3V, and 10Ts.
The above are the standard specifications of our company, and they can be designed according to the special requirements of customers.
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