H01F 29/08
Variable transformers or inductances not covered by group h01f21/00: with core, coil
Official title: with core, coil, winding, or shield movable to offset variation of voltage or phase shift, e.g. induction regulators
H01F29/08 (Variable transformers or inductances not covered by group h01f21/00: with core, coil) appears on 108 US grants and 73 published applications in this corpus.
Search patents in H01F- Granted patents
- 108
- Published applications
- 73
- Assignees
- 91
- Inventors
- 211
- Latest grant
- 2 Dec 2025
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 9 | 0 |
| 1977 | 6 | 0 |
| 1978 | 7 | 0 |
| 1979 | 4 | 0 |
| 1980 | 2 | 0 |
| 1981 | 1 | 0 |
| 1982 | 1 | 0 |
| 1983 | 0 | 0 |
| 1984 | 1 | 0 |
| 1985 | 2 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 2 | 0 |
| 1989 | 1 | 0 |
| 1990 | 1 | 0 |
| 1991 | 0 | 0 |
| 1992 | 1 | 0 |
| 1993 | 0 | 0 |
| 1994 | 1 | 0 |
| 1995 | 3 | 0 |
| 1996 | 0 | 0 |
| 1997 | 1 | 0 |
| 1998 | 0 | 0 |
| 1999 | 1 | 0 |
| 2000 | 1 | 0 |
| 2001 | 2 | 1 |
| 2002 | 3 | 1 |
| 2003 | 4 | 1 |
| 2004 | 0 | 2 |
| 2005 | 1 | 0 |
| 2006 | 1 | 2 |
| 2007 | 2 | 3 |
| 2008 | 2 | 2 |
| 2009 | 0 | 1 |
| 2010 | 1 | 2 |
| 2011 | 0 | 1 |
| 2012 | 0 | 1 |
| 2013 | 1 | 0 |
| 2014 | 2 | 4 |
| 2015 | 1 | 4 |
| 2016 | 4 | 6 |
| 2017 | 3 | 10 |
| 2018 | 6 | 5 |
| 2019 | 4 | 7 |
| 2020 | 10 | 5 |
| 2021 | 5 | 3 |
| 2022 | 2 | 2 |
| 2023 | 2 | 5 |
| 2024 | 4 | 2 |
| 2025 | 3 | 3 |
By publication year. Applications have been published since 2001.
Subgroups
Granted patents
Recent patents
- Variable inductor device comprising first and second planar loops configured to be separable by pivoting about a hinge2 Dec 2025US 12,488,938 B2Lam Research Corporation
- Power inductor with variable width air gap10 Jun 2025US 12,327,669 B2Ford Global Technologies, LLC
- Inductive component and method for adjusting an inductance27 May 2025US 12,315,671 B2Philip Morris Products S. A.
- Variable inductive displacement sensor, associated device, system and aircraft17 Sep 2024US 12,092,495 B2Safran Electronics & Defense
- Dual range position sensing configurations for variable differential transformers25 Jun 2024US 12,018,768 B2Hamilton Sundstrand Corporation
- Systems and methods for variable differential transformers secondaries with single rail bias8 May 2025US 2025/0149238 A1Woodward, Inc.
- System for parametric resonant varying inductance13 Mar 2025US 2025/0087400 A1Elan Research - 9456-4424 QuéBec Inc.
- Coupled inductor with adjustable leakage inductance23 Jan 2025US 2025/0029779 A1Itg Electronics, Inc.
- Resonant transformers with calibratable flux-shunt21 Nov 2024US 2024/0387096 A1Enphase Energy, Inc.
- Pcb-based stranded, twisted excitation windings in rotary transformers24 Oct 2024US 2024/0355540 A1BorgWarner Inc.
Most cited
By later US patents
- Metal vapor electric discharge lamp system93US 4,160,193 A1979
- Multi-range, high-speed A.C. over-current protection means including a static switch47US 3,932,791 A1976
- Displacement - electricity transducer42US 4,013,911 AHitachi, Ltd. · 1977
- Use of variable impedance having rotating core to control coil sputter distribution41US 6,254,738 B1APPLIED Materials.Inc. · 2001
- Linear variable phase transformer with constant magnitude output33US 4,282,485 APneumo Corporation · 1981