Prof. Dr. Thorsten Jungmann (last updated 2026-05-05)
Alexander Graham Bell (1847–1922) was a Scottish-born inventor, linguist and teacher of the deaf who worked for most of his life in the USA and Canada. His father and grandfather had studied the science of speech and the correction of speech defects – a background that shaped Bell’s lifelong interest in the acoustic transmission of speech.
Bell’s best-known invention is the telephone, for which he was granted US Patent No. 174 465 in 1876. In the same year he achieved the first intelligible telephone transmission. By founding the Bell Telephone Company (1877) – from which AT&T and the Bell Telephone Laboratories later emerged – he laid the foundation for modern communications engineering.
In electrical engineering you meet his name above all as a unit for logarithmic ratios: the bel (unit symbol ) was named in his honour and describes the ratio of two powers as a decimal logarithm, . As the bel is too large a unit for practical use, the tenth part of it – the decibel () – has become established as the standard. It is used universally in electrical engineering, acoustics and communications engineering to state gains and attenuations.
Reference and further reading:
https://en.wikipedia.org/wiki/Alexander_Graham_Bell
Image source: Wikimedia Commons (public domain)
