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Marconi magnetic
detector, (foto Fons Vanden Berghen) |
In 1914 various systems for detecting radiosignals were being improved. In 1914 W.H. Marchant writes the following article about detectors:
Detectors of electrical oscillations
The detectors used in Radio-Telegraphy may be broadly divided into two classes: those that are potential actuated and those that are current actuated: the former are always joined across the terminals of the condenser, as the potential differences are largest there, and the latter or current-actuated variety are connected in series with the condenser. Detectors may also be further subdivided into classes -namely, imperfect contact devices, such as the Marconi coherer; rectifying devices, such as the Fleming valve and the carborundum detector; electrolytic detectors, as those of Fessenden and Schlomilch; the thermo-electric type, formed of galena against grafhite, and various other combinations, and those that depend for their action on the alternation of their magnetic properties: in this class is the Marconi magnetic detector.