FR639320A - Improvements to hearing devices - Google Patents
Improvements to hearing devicesInfo
- Publication number
- FR639320A FR639320A FR639320DA FR639320A FR 639320 A FR639320 A FR 639320A FR 639320D A FR639320D A FR 639320DA FR 639320 A FR639320 A FR 639320A
- Authority
- FR
- France
- Prior art keywords
- hearing devices
- hearing
- devices
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R19/00—Electrostatic transducers
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
- Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US142790A US1722347A (en) | 1926-10-20 | 1926-10-20 | Acoustic apparatus |
Publications (1)
Publication Number | Publication Date |
---|---|
FR639320A true FR639320A (en) | 1928-06-19 |
Family
ID=22501288
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
FR639320D Expired FR639320A (en) | 1926-10-20 | 1927-08-11 | Improvements to hearing devices |
Country Status (6)
Country | Link |
---|---|
US (1) | US1722347A (en) |
BE (1) | BE345155A (en) |
DE (1) | DE519901C (en) |
FR (1) | FR639320A (en) |
GB (1) | GB279390A (en) |
NL (1) | NL22541C (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2500643A (en) * | 1946-12-07 | 1950-03-14 | Bell Telephone Labor Inc | Condenser transducer independent of ambient atmospheric conditions |
JPS5121791B2 (en) * | 1972-08-04 | 1976-07-05 |
-
0
- BE BE345155D patent/BE345155A/xx unknown
- NL NL22541D patent/NL22541C/xx active
-
1926
- 1926-10-20 US US142790A patent/US1722347A/en not_active Expired - Lifetime
-
1927
- 1927-07-21 GB GB19382/27A patent/GB279390A/en not_active Expired
- 1927-07-30 DE DEE36023D patent/DE519901C/en not_active Expired
- 1927-08-11 FR FR639320D patent/FR639320A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
US1722347A (en) | 1929-07-30 |
NL22541C (en) | |
GB279390A (en) | 1928-10-22 |
DE519901C (en) | 1931-03-06 |
BE345155A (en) |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
FR653092A (en) | Improvements to hearing devices | |
FR627183A (en) | Improvements to television sets | |
FR639320A (en) | Improvements to hearing devices | |
FR631777A (en) | Improvements to cinematographic devices | |
FR645452A (en) | Improvements to telephone devices | |
FR678302A (en) | Improvements to vibratory devices | |
FR626958A (en) | Improvements to metallurgical devices | |
FR32969E (en) | Improvements to piezoelectric devices | |
FR638449A (en) | Improvements to winding devices | |
FR638201A (en) | Improvements to refrigeration devices | |
FR696762A (en) | Improvements to electro-acoustic devices | |
FR620709A (en) | Improvements to phonographic devices | |
FR598631A (en) | Improvements to hearing devices | |
FR589797A (en) | Improvements to hearing devices | |
FR631244A (en) | Improvements to so-called devices | |
FR640261A (en) | Improvements to cinematographic devices | |
FR637950A (en) | Improvements to cinematographic devices | |
FR626964A (en) | Improvements to cinematographic devices | |
FR612622A (en) | Improvements to cinematographic devices | |
FR33271E (en) | Improvements to cinematographic devices | |
FR703070A (en) | Improvements to hearing devices | |
FR644597A (en) | Improvements to pumping devices | |
FR620919A (en) | Improvements to flying devices | |
FR638204A (en) | Improvements to telegraph receiving devices | |
FR638203A (en) | Improvements to telegraph receiving devices |