H04R 21/00
Variable-resistance transducers
Official title: Variable-resistance transducers (gaseous resistance transducers H04R23/00; magneto-resistive transducers H04R23/00)
H04R21/00 (Variable-resistance transducers) appears on 34 US grants and 26 published applications in this corpus.
Search patents in H04R- Granted patents
- 34
- Published applications
- 26
- Assignees
- 36
- Inventors
- 106
- Latest grant
- 12 May 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 1 | 0 |
| 1978 | 0 | 0 |
| 1979 | 1 | 0 |
| 1980 | 3 | 0 |
| 1981 | 0 | 0 |
| 1982 | 0 | 0 |
| 1983 | 1 | 0 |
| 1984 | 0 | 0 |
| 1985 | 0 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 1 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 1 | 0 |
| 1999 | 0 | 0 |
| 2000 | 1 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 0 | 0 |
| 2004 | 0 | 0 |
| 2005 | 0 | 1 |
| 2006 | 0 | 0 |
| 2007 | 1 | 1 |
| 2008 | 0 | 0 |
| 2009 | 0 | 2 |
| 2010 | 0 | 0 |
| 2011 | 1 | 2 |
| 2012 | 0 | 2 |
| 2013 | 1 | 1 |
| 2014 | 2 | 2 |
| 2015 | 4 | 3 |
| 2016 | 1 | 2 |
| 2017 | 2 | 1 |
| 2018 | 1 | 3 |
| 2019 | 2 | 1 |
| 2020 | 2 | 0 |
| 2021 | 0 | 0 |
| 2022 | 1 | 2 |
| 2023 | 1 | 2 |
| 2024 | 0 | 1 |
| 2025 | 2 | 0 |
| 2026 | 1 | 0 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Vibration sensor12 May 2026US 12,627,916 B2Shenzhen Shokz Co., Ltd.
- Microphone apparatus24 Jun 2025US 12,342,113 B2Nokia Technologies Oy
- Spectral compensation filters for close proximity sound sources14 Jan 2025US 12,200,438 B2Meridian Audio Ltd.
- Variable voltage phantom power supply assembly and a method for customizing performance characteristics of a microphone24 Oct 2023US 11,800,282 B1Copperline Ranch
- Reactive silent speaker device for simulating harmonic nonlinearities of a loudspeaker31 May 2022US 11,348,568 B2AMP Devices, LLC
- Roll-to-roll micro-scale thermal wire microphone4 Jul 2024US 2024/0223969 A1Nikon Corporation
- Vibration sensor9 Nov 2023US 2023/0362525 A1Shenzhen Shokz Co., Ltd.
- A Microphone Apparatus12 Oct 2023US 2023/0328415 A1Nokia Technologies Oy
- Spectral compensation filters for close proximity sound sources8 Dec 2022US 2022/0394379 A1Meridian Audio Ltd.
- Reactive Silent Speaker Device for Simulating Harmonic Nonlinearities of a Loudspeaker3 Mar 2022US 2022/0068254 A1AMP Devices, LLC
Most cited
By later US patents
- Mechanically biased semiconductor strain sensitive microphone38US 4,182,937 AInternational Standard Electric Corporation · 1980
- Miniature acoustic detector based on electron surface tunneling20US 7,280,436 B2Corporation for National Research Initiatives · 2007
- Acoustic pressure transducer13US 8,705,774 B2Hewlett-Packard Development Company, L. P. · 2014
- Environmentally sealed acoustic transducer coupling12US 5,729,508 ARosemount Aerospace Inc. · 1998
- Magnetoresistive microphone and acoustic sensing devices7US 5,450,372 AAT&T Corp. · 1995