Dunand's microphone
Datecirca 1878
Inventory Number8099
ClassificationTelephone
Subject
Maker
A. Dunand
c. 1881
Place of Origin
Dimensions11.3 × 11.3 × 3 cm (4 7/16 × 4 7/16 × 1 3/16 in.)
Material
DescriptionAn early carbon transmitter used in France. The word "microphone" was used to describe a transmitter which modulated an electric current at the contact points of two or more elements of carbon in a circuit.
The transmitter has a circular, 2-layer carved wooden frame with two binding posts protruding from the frame at a 90° angle to one another. Inside, the frame holds two metallic diaphragms lightly in contact, with a bead of carbon suspended by a wire between contact points of two carbon lozenges mounted between the two diaphragms. The layers of the frame are held together by three screws, which can be adjusted to regulate the tension of the carbon bead against the carbon bars.
Mounted on the back of the frame is a t-shaped assembly with two screw knobs, two knurled-edge thumb nuts and two metal cylinders mounted on it.
By speaking into one of the plates, resistance is produced and voice may be transmitted.
The transmitter has a circular, 2-layer carved wooden frame with two binding posts protruding from the frame at a 90° angle to one another. Inside, the frame holds two metallic diaphragms lightly in contact, with a bead of carbon suspended by a wire between contact points of two carbon lozenges mounted between the two diaphragms. The layers of the frame are held together by three screws, which can be adjusted to regulate the tension of the carbon bead against the carbon bars.
Mounted on the back of the frame is a t-shaped assembly with two screw knobs, two knurled-edge thumb nuts and two metal cylinders mounted on it.
By speaking into one of the plates, resistance is produced and voice may be transmitted.
Signedunsigned
Curatorial RemarksOld tag: "Dunand's MICROPHONE 8099"
FunctionConversion of sound into electrical signals for transmission over a distance
ProvenanceJefferson Laboratory, Physics Department, Harvard University
Sylvania
Date: late 19th-early 20th Century
Object number: RS0368
Société Générale des Téléphones
Date: 1880
Object number: 8029
F. F. Metzger
Date: circa 1927
Accessories: wooden box lined with velvet cushioning;
strain gauge;
iron bar;
steel rod contact points (2);
nails (3) wrapped in paper;
manual;
single stationery paper;
pamphlet (price list)
Object number: 1999-1-0065
Western Electric Company
Date: 1920-1930
Object number: RS1359
F. F. Metzger
Date: early 20th Century
Accessories: brown leatherbound wood case with purple stuffed velvet lining two metal locks in front;
steel rod contact points (4);
metal bar;
strain gauge;
card describing gauge ratio
Object number: 1999-1-0084