photophone

E44558

The photophone was an early communication device that transmitted sound on a beam of light, serving as a precursor to modern fiber-optic technology.

Aliases (1)

Statements (48)
Predicate Object
instanceOf invention
optical communication device
telecommunications device
alsoKnownAs radiophone using light (historical description)
category historical communication technology
communicationPrinciple modulation of light intensity by sound
demonstratedBy Alexander Graham Bell
demonstrationLocation Washington, D.C.
demonstrationYear 1880
era late 19th century
field electrical engineering
optics
telecommunications
historicalSignificance early example of optical wireless communication
first device to achieve wireless voice communication via light
inspired later optical communication research
inventedBy Alexander Graham Bell
Charles Sumner Tainter
inventionYear 1880
inventorAffiliation Bell Telephone Company
Volta Laboratory
limitation requirement for line-of-sight
sensitivity to atmospheric disturbances
sensitivity to weather conditions
modulatorType thin reflective diaphragm
vibrating mirror
operatingRange several hundred meters
outputConversion electrical signal to sound
light to electrical signal
patentFiledBy Alexander Graham Bell
Charles Sumner Tainter NERFINISHED
patentFiledIn United States
patentFiledYear 1880
powerSource artificial light
sunlight
precursorTo fiber-optic communication
optical telecommunication systems
receiverMaterial selenium
receiverType photoelectric cell
selenium cell
relatedTo fiber-optic cable
free-space optical communication
telephone
signalCarrier visible light
transmissionType wireless
transmits sound
voice
usesMedium light beam

Referenced by (2)
Subject (surface form when different) Predicate
Alexander Graham Bell
invented
Alexander Graham Bell
notableInvention

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