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Greenleaf Whittier Pickard

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Greenleaf Whittier Pickard (February 14, 1877, Portland, Maine - January 8, 1956, Newton, Massachusetts) was a United States radio pioneer. Pickard was a researcher in the early days of wireless. He experimented with crystal detectors, used in crystal radio receivers. On August 30, 1906 he filed a patent for a silicon crystal detector, which was granted on November 20, 1906.^[1] Pickard's detector was revolutionary in that he found that a fine pointed wire known as a "cat's whisker", in delicate contact with a mineral produced the best semiconductor effect. Greenleaf Whittier Pickard was named after his great-uncle, the American Quaker John Greenleaf Whittier (1807-1892).

Patents

U.S. Patent 796,011 - Electrostatic separation
U.S. Patent 796,012 - Electrostatic separation
U.S. Patent 827,115 - Electrostatic separation
U.S. Patent 827,116 - Electrostatic separation
U.S. Patent 836,531 - Means for receiving intelligence communicated by electric waves (silicon detector), 1906
U.S. Patent 840,802 - Electrostatic separator,1907
U.S. Patent 845,316 - Means for receiving intelligence communicated by electric waves (copper sulfate solution detector), 1907
U.S. Patent 876,996 - Intelligence intercommunication by magnetic wave component, 1908
U.S. Patent 877,451 - Means for receiving intelligence communicated by electric waves (spring-loaded detector contact), 1908
U.S. Patent 886,154 - Oscillation receiver (fused zinc oxide detector), 1908
U.S. Patent 888,191 - Oscillation receiver (polished silicon detector, 1908
U.S. Patent 904,222 - Oscillation detecting means (molybdenite detector), 1908
U.S. Patent 912,613 - Oscillation detector and rectifier ("plated" silicon carbide detector with DC bias), G.W. Pickard, 1909
U.S. Patent 912,726 - Oscillation receiver (fractured surface red zinc oxide (zincite) detector), 1909
U.S. Patent 933,263 - Oscillation device (iron pyrite detector), 1909
U.S. Patent 1,104,073 - Detector for wireless telegraphy and telephony (looped or humped springy wire detector contact), 1914
U.S. Patent 1,118,228 - Oscillation detectors (pairs of minerals), 1914
U.S. Patent 1,128,817 - Valve detector for wireless (vacuum tube with conducting shield to drain static), 1915
U.S. Patent 1,185,711 - Receiver for wireless telephony and telegraphy (interrupted or switched circuit instead of rectifier), 1916
U.S. Patent 1,213,250 - Means for receiving intelligence communicated by electric waves (receiving circuit, divided from #836531), 1917
U.S. Patent 1,476,102 - Optical selection of split mica sheets
U.S. Patent 1,561,483 - Distinguishing dielectric sheets
U.S. Patent 1,676,745 - Electrical reactance and method and apparatus
U.S. Patent 1,918,825 - Extreme loading condenser