contact rectifier การใช้

• A "'rectifier "'is an electrical device that cat's whisker " of fine wire pressing on a crystal of galena ( lead sulfide ) to serve as a point-contact rectifier or " crystal detector ".
• A World War II program to manufacture high-purity silicon as the crystal base for the point-contact rectifier was suggested by Frederick Seitz in 1942 and successfully undertaken by the Experimental Station of the E . I du Pont de Nemours Company.