Greenleaf Whittier Pickard

Infobox_Scientist
name = Greenleaf Whittier Pickard

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caption =
birth_date = birth date|1877|2|14
birth_place =
death_date = death date and age|1956|1|8|1877|2|14
death_place =
residence =United States
nationality = American
field = Electrical engineering
work_institution =
alma_mater =
doctoral_advisor =
awards = IEEE Medal of Honor

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. [www.bellsystemmemorial.com/belllabs_transistor1.html. 17:42, 15 March 2006.] 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

* - "Electrostatic separation"
* - "Electrostatic separation"
* - "Electrostatic separation"
* - "Electrostatic separation"
* - "Means for receiving intelligence communicated by electric waves" (silicon detector), 1906
* - "Electrostatic separator",1907
* - "Means for receiving intelligence communicated by electric waves" (copper sulfate solution detector), 1907
* - "Intelligence intercommunication by magnetic wave component", 1908
* - "Means for receiving intelligence communicated by electric waves" (spring-loaded detector contact), 1908
* - "Oscillation receiver" (fused zinc oxide detector), 1908
* - "Oscillation receiver" (polished silicon detector, 1908
* - "Oscillation detecting means" (molybdenite detector), 1908
* - "Oscillation detector and rectifier" ("plated" silicon carbide detector with DC bias), G.W. Pickard, 1909
* - "Oscillation receiver" (fractured surface red zinc oxide (zincite) detector), 1909
* - "Oscillation device" (iron pyrite detector), 1909
*
* - "Detector for wireless telegraphy and telephony" (looped or humped springy wire detector contact), 1914
* - "Oscillation detectors" (pairs of minerals), 1914
* - "Valve detector for wireless" (vacuum tube with conducting shield to drain static), 1915
* - "Receiver for wireless telephony and telegraphy" (interrupted or switched circuit instead of rectifier), 1916
* - "Means for receiving intelligence communicated by electric waves" (receiving circuit, divided from #836531), 1917
* - "Optical selection of split mica sheets"
* - "Distinguishing dielectric sheets"
* - "Electrical reactance and method and apparatus"
*
* - "Extreme loading condenser"

"Reissued"

* - "Means for receiving intelligence communicated by electric waves"

References

;Citations;General
* [http://www.ieee.org/web/aboutus/history_center/biography/pickard.html IEEE History Center: Greenleaf W. Pickard biography]

External links

* [http://www.ieee.org/organizations/history_center/legacies/pickard.html IEEE History Center: Greenleaf W. Pickard]