Museo Galileo
Virtual Museum
Wheatstone's A.B.C. telegraph transmitter
    • Setting:
      Room XVI
    • Inventor:
      Charles Wheatstone
    • Maker:
      Charles Wheatstone
    • Date:
      ca. 1840
    • Materials:
      mahogany, brass, iron
    • Dimensions:
      total height 290 mm, base 439x312 mm
    • Inventory:
    • Wheatstone's A.B.C. telegraph transmitter (Inv. 545)

Wheatstone's telegraph transmitter. Rotating a brass wheel with its letters and numerals moves a large brass gear wheel on the same axis. This causes twin coils to rotate over the poles of a horseshoe permanent magnet and a commutator with two flexible leaf-spring contacts to the screw-terminals. This magneto-electric machine of the Clarke pattern produces a variable number of pulses of current according to the letter sent down the telegraph line. At the receiving station, the pulses released a clock escapement, allowing a pointer to turn until the transmitted letter was indicated. Provenance: Lorraine collections.