Thomas Edison
1847–1931 · Inventor, carbon telephone transmitter
Major contribution
Edison developed a carbon-button transmitter that contributed to the microphone technology used in early public-address systems.
Western Union asked Edison to improve speech transmission in 1877. His carbon transmitter used compressed carbon powder between metal disks, with a diaphragm changing the pressure and therefore the electrical resistance as a person spoke.
The Science Museum preserves an Edison transmitter made in 1878. This work is relevant to live sound as part of the development of carbon microphones, not as evidence that Edison alone invented the microphone or the complete PA system.
Key work
- Western Union speech-transmission development (1877)
- Carbon-button transmitter No. 32 (1878)
- Carbon telephone transmitter, documented in the NPS historical program (2020)
In the chronology
Selected sources
- Edison carbon button transmitter No. 32, 1878 · Science Museum Group
- Thomas Edison and Deafness · National Park Service
- The History of Live Sound – Part 1 · HARMAN Professional Solutions