Biographical notes
History tlc
History telegraph
History telephone
History radio
History  TV
History components
Index Scientists




Calzecchi Onesti



Lapedona (Ascoli Piceno) 14.December.1853*   Monterubbiano (Ascoli Piceno) 25.November.1922

                                                  Detector of electromagnetic waves (coherer)

In 1884 began his studies around the electrical resistance and conductivity of metal limature. And in the same year discovered the properties of metal powders to buy a strong electrical conductivity after several excitations as extra currents, electrical shock, inductions electrostatic etc.. Based on this important achievement and following the research carried in the field, Calzecchi Onesti built the "tube to filings" that many years later, with the name "Coherer" was used by Marconi as a detector of electromagnetic waves in its first unit of wireless telegraphy. This appliance consists of a glass tube containing powdered nickel and silver with traces of mercury, placed between two electrodes steel, in a vacuum. When it is hit by electromagnetic fields, the high resistance of powder, it becomes relatively low and then loses conductivity for percussion (decoherizzazione).
Coherer di Onesti