experimental silicon photosensitive electromotive force cell
date: label: Date made
content: 1940
label: associated date
content: 1940
name: label: associated user
content: unknown
label: associated person
content: Ohl, Russell S.
label: maker
content: Ohl, Russell S.
notes: label: Description (Brief)
content: Engineer Russell Ohl worked at Bell Labs during the 1930s and made a discovery that contributed to the invention of both solar cells and transistors. While researching semiconductors—materials whose ability to conduct electricity can be manipulated—he found positive (P) and negative (N) regions created by impurities in his silicon sample. The barrier between the regions, called a P-N junction, prevented electrons from moving—until he exposed the silicon to sunlight. Then electrons crossed the junction and generated a current, converting sunlight into electrical energy. The silicon rod mounted in this reflector contains a P-N junction across the center and is drawn as figure eight on U.S. Patent 2,402,662, "Light-Sensitive Electric Device," issued to Ohl on 25 June 1946.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Energy & Power
creditLine: label: Credit Line
content: from Russell S. Ohl
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.334949
label: catalog number
content: 334949
label: accession number
content: 314577
label: maker number
content: 10
label: patent number
content: 2402662
objectType: label: Object Name
content: silicon rod
label: Object Name
content: photosensitive electromotive force cell
label: Object Name
content: photovoltaic cell
physicalDescription: label: Measurements
content: overall: 2 1/2 in x 2 in x 1 1/4 in; 6.35 cm x 5.08 cm x 3.175 cm