US2572525A - Microphone with carbon electrodes - Google Patents

Microphone with carbon electrodes Download PDF

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Publication number
US2572525A
US2572525A US41371A US4137148A US2572525A US 2572525 A US2572525 A US 2572525A US 41371 A US41371 A US 41371A US 4137148 A US4137148 A US 4137148A US 2572525 A US2572525 A US 2572525A
Authority
US
United States
Prior art keywords
microphone
electrode
funnel
carbon
housing
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 - Lifetime
Application number
US41371A
Other languages
English (en)
Inventor
Zurich Erich Schircks
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens Schweiz AG
Albiswerk Zuerich AG
Original Assignee
Siemens Albis AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Siemens Albis AG filed Critical Siemens Albis AG
Application granted granted Critical
Publication of US2572525A publication Critical patent/US2572525A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • H04R1/222—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only  for microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R21/00—Variable-resistance transducers
    • H04R21/02—Microphones
    • H04R21/021—Microphones with granular resistance material

Definitions

  • the invention relates to carbon microphones
  • a conical electrode is conductively secured to a diaphragm and influences the granulated carbon contained in a funnel electrode insulatingly secured to the microphone housing.
  • the aim if the invention is to improve such microphones as regards sensitivity, stability of operating properties and evenness of frequency characteristics.
  • a carbon microphone has a funnel electrode provided with groove-like depressions that extend in the direction of the contour lines (generatrices) of the funnel surface.
  • the space between the diaphragm and the back of the housing is divided into two chambers by a partition which is perforated in addition to the central aperture necessary for the passage of the diaphragm electrode.
  • Fig. 1 is a diametrical cross section of a microphone according to the invention
  • Fig. 2 an exploded perspective view of its individual components.
  • the diaphragm I of the microphone consists, for example, of an aluminum foil and has a conical electrode 2 conductivel cemented thereto.
  • the rigid portion of the microphone housing 3 carries a funnel electrode 4.
  • , 42 and metal components 43, 44 serve to fasten the funnel electrode.
  • An insulating member 45 has a bore for the passage of the connection leads of the microphone.
  • the funnel surface of electrode 4 has groove-like depressions 46 extending along contour lines (generatrices) of that surface.
  • the upper portion 41 of the funnel surface is rendered non-conducting by the application of a coat of insulating varnish.
  • An intermediate wall 5 partitions the space between diaphragm I and the back of the housing 3 and has a central opening 5
  • is inserted to improve the sealing of the funnel electrode, i. e. to prevent the escape of the carbon granules disposed between the two electrodes.
  • a protective lid 32 has sound holes 33 arranged in a concentric circle.
  • a spacing ring 34 separates the diaphragm I from the partition 5.
  • a flanged ring 35 holds the entire microphone together.
  • the groove-shaped depressions in the direction of the contour lines of the surface of the funnel electrode perform the function of carbon granule storage chambers and control the flow of the granules between the two electrodes. Due to acoustical or mechanical vibration, the detrimental interruption effect otherwise occurring because of the adhesion of the granules at individual points when the microphone has been switched out of circuit, is remedied and the full sensitivity of the microphone restored. Microphones with electrodes designed in this manner require smaller carbon granules than those of the special, for instance star-shaped, carbon-granules pot already proposed for the known types of microphone.
  • the perforated partition which subdivides the space between the diaphragm and the back portion of the housing into two chambers of limited inter-communication serves the purpose of providing, with the aid of the perforations, a damping effect operative only on a particular frequency band.
  • the procedure is such that with a minimum of apertures 52 indicated by experience, the frequency course of the microphone is determined, whereupon, according to the result, the apertures are enlarged until the frequency course complies with requirements.
  • the felt ring 6 on the one hand prevents the carbon granules from escaping and on the other hand covers the apertures in the intermediate wall, thereby subdividing them into a large number of small apertures.
  • the conical electrode may be cemented to the diaphragm with the aid of some conductive substance. For this purpose an in itself non-conducting cement can be mixed with, for instance, carbon dust.
  • a microphone comprising a housing, a diaphragm mounted on said housing, a conical electrode secured to said diaphragm, a funnel electrode secured to said housing and having a funnel surface coaxial with and spaced from said conical electrode, said funnel electrode having grooves in said surface extendin from the funnel point toward the funnel periphery, and carbon granules between said grooved surface and said conical electrode.
  • a microphone comprising a. housing, a, di-
  • aphragm mounted in said housing, a conical carbon electrode conductively secured to said d1- aphragm, a funnel electrode insulatedly secured to said hOuSing opposite said conical electrode and having a funnel surface substantially con- 5 centric to, and spaced from said conical electrode, said funnel ielectrode 'having grooves; in said surface extending substantially along respective contour lines of said surface, and carbon granules between said grooved surface and isaid conical electrode. 551,588 3.
  • a microphone comprising a housing, a"dia-' 5 3 395 phragm mounted on said'housing, a; partition 77 409 extending within said housing'rand-dividing it 11 1 7 231 into two chambers of which one is bordered by 15 2,140,859 said diaphragm, said partition. having-a central.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
US41371A 1947-08-06 1948-07-29 Microphone with carbon electrodes Expired - Lifetime US2572525A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH2572525X 1947-08-06

Publications (1)

Publication Number Publication Date
US2572525A true US2572525A (en) 1951-10-23

Family

ID=4570209

Family Applications (1)

Application Number Title Priority Date Filing Date
US41371A Expired - Lifetime US2572525A (en) 1947-08-06 1948-07-29 Microphone with carbon electrodes

Country Status (6)

Country Link
US (1) US2572525A (en))
BE (1) BE484178A (en))
CH (1) CH269350A (en))
DE (1) DE874019C (en))
FR (1) FR969788A (en))
NL (1) NL70171C (en))

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE954967C (de) * 1952-11-01 1956-12-27 Standard Elek K Ag Kohlemikrofon mit einer beweglichen und einer festen Elektrode, die in mehrere Teilelektroden unterteilt ist
DE1234267B (de) * 1964-04-04 1967-02-16 Telefonbau Kohlemikrofon

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US557588A (en) * 1896-04-07 Telephony
US563395A (en) * 1896-07-07 Telephone-transmitter
US778409A (en) * 1903-04-20 1904-12-27 Oscar M Frykman Telephone apparatus.
US1117231A (en) * 1911-11-13 1914-11-17 Western Electric Co Loud-speaking transmitter.
US2140859A (en) * 1936-12-14 1938-12-20 Siemens Ag Telephone transmitter
US2149628A (en) * 1935-09-16 1939-03-07 Associated Electric Lab Inc Telephone transmitter
GB513160A (en) * 1938-03-01 1939-10-05 Donald Mcmillan Improvements in or relating to microphones
US2179733A (en) * 1934-11-27 1939-11-14 Siemens Brothers & Co Ltd Microphone
US2435920A (en) * 1943-09-20 1948-02-10 Electro Voice Mfg Co Inc Balanced granular microphone

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US557588A (en) * 1896-04-07 Telephony
US563395A (en) * 1896-07-07 Telephone-transmitter
US778409A (en) * 1903-04-20 1904-12-27 Oscar M Frykman Telephone apparatus.
US1117231A (en) * 1911-11-13 1914-11-17 Western Electric Co Loud-speaking transmitter.
US2179733A (en) * 1934-11-27 1939-11-14 Siemens Brothers & Co Ltd Microphone
US2149628A (en) * 1935-09-16 1939-03-07 Associated Electric Lab Inc Telephone transmitter
US2140859A (en) * 1936-12-14 1938-12-20 Siemens Ag Telephone transmitter
GB513160A (en) * 1938-03-01 1939-10-05 Donald Mcmillan Improvements in or relating to microphones
US2435920A (en) * 1943-09-20 1948-02-10 Electro Voice Mfg Co Inc Balanced granular microphone

Also Published As

Publication number Publication date
DE874019C (de) 1953-04-20
BE484178A (en))
NL70171C (en))
CH269350A (de) 1950-06-30
FR969788A (fr) 1950-12-26

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