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Elisha Gray patent model telegraph repeater
From the collection of National Museum of American History. Free to download, adapt and use — no permission needed.
About this work
Telegraph repeaters amplified electrical signals in a telegraph line. Telegraph messages traveled as a series of electrical pulses through a wire from a transmitter to a receiver. Short pulses made a dot, slightly longer pulses a dash. The pulses faded in strength as they traveled through the wire, limiting the distance a message could travel. Repeaters remedied that problem by detecting a weak signal and using a local power source to re-energize and re-transmit the signal down the line.
National Museum of American History’s own descriptionCredit lineElisha Gray patent model telegraph repeater. 1871. Gray, Elisha. National Museum of American History. CC0.
