H01F 27/34
Special means for preventing or reducing unwanted electric or magnetic effects
Official title: Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
H01F27/34 (Special means for preventing or reducing unwanted electric or magnetic effects) appears on 2,786 US grants and 3,467 published applications in this corpus.
Search patents in H01F- Granted patents
- 2,786
- Published applications
- 3,467
- Assignees
- 1,180
- Inventors
- 6,216
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 11 | 0 |
| 1977 | 14 | 0 |
| 1978 | 6 | 0 |
| 1979 | 5 | 0 |
| 1980 | 3 | 0 |
| 1981 | 7 | 0 |
| 1982 | 9 | 0 |
| 1983 | 4 | 0 |
| 1984 | 13 | 0 |
| 1985 | 14 | 0 |
| 1986 | 9 | 0 |
| 1987 | 7 | 0 |
| 1988 | 5 | 0 |
| 1989 | 7 | 0 |
| 1990 | 4 | 0 |
| 1991 | 7 | 0 |
| 1992 | 17 | 0 |
| 1993 | 7 | 0 |
| 1994 | 6 | 0 |
| 1995 | 10 | 0 |
| 1996 | 6 | 0 |
| 1997 | 7 | 0 |
| 1998 | 11 | 0 |
| 1999 | 13 | 0 |
| 2000 | 13 | 0 |
| 2001 | 22 | 7 |
| 2002 | 21 | 53 |
| 2003 | 49 | 48 |
| 2004 | 36 | 49 |
| 2005 | 38 | 53 |
| 2006 | 49 | 74 |
| 2007 | 60 | 72 |
| 2008 | 47 | 106 |
| 2009 | 47 | 97 |
| 2010 | 75 | 101 |
| 2011 | 89 | 71 |
| 2012 | 71 | 66 |
| 2013 | 45 | 86 |
| 2014 | 54 | 137 |
| 2015 | 65 | 189 |
| 2016 | 102 | 134 |
| 2017 | 124 | 184 |
| 2018 | 163 | 259 |
| 2019 | 187 | 267 |
| 2020 | 186 | 232 |
| 2021 | 184 | 236 |
| 2022 | 195 | 235 |
| 2023 | 195 | 224 |
| 2024 | 178 | 212 |
| 2025 | 172 | 162 |
| 2026 | 117 | 113 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Method and composition for lightning protection6 Oct 2026US 12,753,547 B2
- Variable magnetic layer for wireless charging6 Oct 2026US 12,755,898 B23M Innovative Properties Company
- Electric transformer with an increased total leakage impedance29 Sep 2026US 12,749,616 B2Exxelia
- Tap changer and a transformer arrangement comprising the tap changer29 Sep 2026US 12,749,618 B2Hitachi Energy Ltd
- Polymer and elastomer compositions having carbon nanostructure additives and articles formed therefrom for use in EMI and RFI shielding and in pressure sensing seals having quantum tunneling composite effects22 Sep 2026US 12,742,065 B2Greene, Tweed Technologies, Inc.
- Direct Current Quantum Magnetic Transformer and Related Energy Saving Devices and Methods1 Oct 2026US 2026/0302048 A1Harmonify AB
- Layered double-d coil for wireless power transfer systems1 Oct 2026US 2026/0302836 A1Tennessee Technological University
- Coil component, and substrate with integrated coil24 Sep 2026US 2026/0290682 A1Rohm Co., Ltd.
- Quick assembly common mode filter10 Sep 2026US 2026/0269121 A1Tai-Tech Advanced Electronics Co., Ltd.
- Planar coil array, and displacement sensor27 Aug 2026US 2026/0251480 A1Hitachi Astemo, Ltd.
Most cited
By later US patents
- System and method for inductive charging of portable devices499US 8,169,185 B2Mojo Mobility, Inc. · 2012
- Inductive battery charger system with primary transformer windings formed in a multi-layer structure297US 7,164,255 B2City University of Hong Kong · 2007
- Planar transformer power supply266US 7,502,234 B2Aaron Medical Industries, Inc. · 2009
- Planar inductive battery charging system223US 7,576,514 B2Cityu Research Limited · 2009
- Planar printed circuit-board transformers with effective electromagnetic interference (EMI) shielding216US 6,888,438 B2City University of Hong Kong · 2005