GB473776A - Improvements in or relating to public address systems - Google Patents

Improvements in or relating to public address systems

Info

Publication number
GB473776A
GB473776A GB1454136A GB1454136A GB473776A GB 473776 A GB473776 A GB 473776A GB 1454136 A GB1454136 A GB 1454136A GB 1454136 A GB1454136 A GB 1454136A GB 473776 A GB473776 A GB 473776A
Authority
GB
United Kingdom
Prior art keywords
address systems
relating
condenser
public address
loudspeaker
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
Application number
GB1454136A
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.)
EDGAR CHARLES BROWN
RECEIVER FOR METROPOLITAN
Original Assignee
EDGAR CHARLES BROWN
RECEIVER FOR METROPOLITAN
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 EDGAR CHARLES BROWN, RECEIVER FOR METROPOLITAN filed Critical EDGAR CHARLES BROWN
Priority to GB1454136A priority Critical patent/GB473776A/en
Publication of GB473776A publication Critical patent/GB473776A/en
Expired legal-status Critical Current

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
    • H04R27/00—Public address systems

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Alarm Systems (AREA)

Abstract

473,776. Public - address systems. METROPOLITAN POLICE DISTRICT, RECEIVER FOR, and BROWN, E. C. May 22, 1936, No. 14541. [Class 40 (iv)] [Also in Group XL] In a system in which a microphone or other pick-up device a feeds a loudspeaker c through an amplifier comprising two valves, e.g. a triode b1 and pentode b2, coupled by a transformer b3, the amplifier is adapted to generate low frequency oscillations to produce a warning note in the loudspeaker by the operation of a switch h which connects a back-coupling condenser f between the anodes of the valves and a tuning condenser g across the secondary of the transformer b3. Each condenser may have a capacity of À001 mf.
GB1454136A 1936-05-22 1936-05-22 Improvements in or relating to public address systems Expired GB473776A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1454136A GB473776A (en) 1936-05-22 1936-05-22 Improvements in or relating to public address systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1454136A GB473776A (en) 1936-05-22 1936-05-22 Improvements in or relating to public address systems

Publications (1)

Publication Number Publication Date
GB473776A true GB473776A (en) 1937-10-20

Family

ID=10043063

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1454136A Expired GB473776A (en) 1936-05-22 1936-05-22 Improvements in or relating to public address systems

Country Status (1)

Country Link
GB (1) GB473776A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2164523A (en) * 1984-09-15 1986-03-19 Crystalate Electronics Electronic alarm sounder

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2164523A (en) * 1984-09-15 1986-03-19 Crystalate Electronics Electronic alarm sounder

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