Dolbear condenser receiver
Date1878-1880
Inventory Number8042a
ClassificationTelephone
Subject
Maker
Amos E. Dolbear
1837 - 1910
Cultural Region
Place of Origin
Dimensionswithout cord: 5.4 × 9.5 cm (2 1/8 × 3 3/4 in.)
Material
DescriptionA condenser telephone receiver, created by Amos E. Dolbear. Dolbear was a professor of Physics at Tufts University, and was an admirer of Alexander Graham Bell. He later formed his own telephone company and sued Bell for credit for his contributions to telephone development.
Dolbear's device uses a permanent magnet rather than one requiring electrification, and has a transmitter which makes a spark jump between two condenser points in a series. The device has two metal diaphragms in series, one of which vibrates while the other vibrates, each forming a terminal of an induction coil.
Dolbear's condenser receiver is made of hard rubber, and consists of a short cylindrical piece with a rounded, knob-shaped handle. The face of the telephone has a molded, rounded bowl shaped earpiece/mouthpiece with a circular opening at the base. On one side of the cylinder is a small metal eyehook for hanging the device; on the other side, two tubular metal ports provide jacks or connection points for a pair of jacquard patterned cloth-covered electrical wire. The wires are bound together for most of their length, and then separate at the other end into two separate cords, each tipped by a metal electrical pin plug.
Items 8042a and 8042b are very similar.
Inscribed on handle, "90"
Dolbear's device uses a permanent magnet rather than one requiring electrification, and has a transmitter which makes a spark jump between two condenser points in a series. The device has two metal diaphragms in series, one of which vibrates while the other vibrates, each forming a terminal of an induction coil.
Dolbear's condenser receiver is made of hard rubber, and consists of a short cylindrical piece with a rounded, knob-shaped handle. The face of the telephone has a molded, rounded bowl shaped earpiece/mouthpiece with a circular opening at the base. On one side of the cylinder is a small metal eyehook for hanging the device; on the other side, two tubular metal ports provide jacks or connection points for a pair of jacquard patterned cloth-covered electrical wire. The wires are bound together for most of their length, and then separate at the other end into two separate cords, each tipped by a metal electrical pin plug.
Items 8042a and 8042b are very similar.
Inscribed on handle, "90"
Signedunsigned
Inscribedinscribed on handle: 90
Curatorial RemarksOld tag: "Dolbear Condenser Receiver 8042a".
Items 8042a and 8042b are very similar.
FunctionA condenser telephone receiver
ProvenanceJefferson Laboratory, Physics Department, Harvard University
American Speaking Telephone Company
Date: circa 1878
Object number: 8041
Rudolph Koenig
Date: circa 1863
Accessories: repeater (item 8000b)
Object number: 8000a
Harvard Cyclotron Laboratory
Date: 1947-2002
Object number: 2003-1-0291
Thomas Alva Edison
Date: circa 1878
Accessories: telephone receiver (8040a)
Object number: 8040b
See also/See also
