A Treatise Upon Wireless Telegraphy and Telephony (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 Excerpt: ... sending. After long usage, silicon becomes less sensitive, due in a great extent to the accumulation of grease and dirt upon its surface. This may be removed successfully by washing the crystal with Carbon Disulphide, and afterward with soap and water, and thoroughly drying. Also, from continued burnouts, the obtainable points of good contact may become charred, thus necessitating chipping off the outside of the crystal to obtain new points. Although there may not be a great quantity of extremely sensitive points upon one piece of this mineral, it ranks above the Carborundum in sensitiveness, and next to the Perikon. The Perikon Detector. A cut of the Perikon Detector is shown in Fig. 3 as manufactured and sold by the Wireless Specialty Apparatus Company of New York. It consists of a rubber base, upon which is held a cup containing crystals of zincite, perhaps seven or eight in number, depending upon their size. To an adjustable arm is mounted a cup containing a crystal of chalcopyrite. A spring regulates the pressure between the two crystals in use, and it is found that too great a pressure lowers the sensitiveness in a marked degree. Like the silicon detector, no two points are alike, some being better than others. The movable arm must then be adjusted until a sensitive point is found. The crystals can be cleaned in the same manner as those of the silicon detector. This is one of the most, if not the most sensitive detector known. Perhaps its greatest faults are susceptibility to burn outs, the remedy being the same as for the silicon; jarring out of adjustment, a remedy for which is placing the detector stand upon felt, or some other shock absorber; loss of sensitiveness, which occurs after about six months use, the only remedy being to obtain a set of ...