1. telephone, carbon A telephone transmitter based on the use of carbon as a material whose resistance is varied by the degree of pressure brought to bear upon it. Undoubtedly the surface contact between the carbon and the other conducting material has much to do with the action. Many carbon telephones have been invented. Under Telephone the Blake transmitter is described, which is a carbon telephone transmitter. The Edison carbon transmitter is shown in section in the cut. E is the mouth piece and D the diaphragm. I is a carbon disc with adjusting screw V. A platinum plate B B, with ivory button b, is attached to the upper surface of the carbon disc. C C is an insulating ring. The wire connections shown bring the disc into circuit. It is connected like a Blake transmitter. It is now but little used.
Definitions of telephone, carbon
