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US2558670A
|
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Electrical apparatus
|
|
US2551447A
|
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Electrodynamic speaker
|
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US2558669A
|
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Apparatus triggered by recorded signals
|
|
US2526516A
|
|
Sound and picture system with manual and electrical advance of the film in response to a film deformation
|
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US2551350A
|
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Electrical apparatus
|
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US2466634A
|
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Electrical apparatus
|
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US2455471A
|
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Electrical apparatus for loudspeaker systems
|
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US2551349A
|
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Slide film projector with film advance controlled by a sound reproducing system
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US2500063A
|
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Electric siren
|
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GB601924A
|
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Improvements in or relating to an electrical oscillating system having protective means
|
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US2433250A
|
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Loud-speaker
|
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US2496589A
|
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Double diaphragm loud-speaker
|
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US2454618A
|
|
Protective circuits for electronic equipment
|
|
US2423037A
|
|
Electrodynamic loud-speaker
|
|
US2386964A
|
|
Loud-speaker
|
|
US2345202A
|
|
Portable projection apparatus
|
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US2296489A
|
|
Phonograph
|
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GB497490A
|
|
Selective tuning mechanism for radio receivers
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US2093494A
|
|
Selective tuning mechanism for radio receivers
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US1855836A
|
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Sound producing device
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