US2488369A - Selenium rectifier - Google Patents
Selenium rectifier Download PDFInfo
- Publication number
- US2488369A US2488369A US514371A US51437143A US2488369A US 2488369 A US2488369 A US 2488369A US 514371 A US514371 A US 514371A US 51437143 A US51437143 A US 51437143A US 2488369 A US2488369 A US 2488369A
- Authority
- US
- United States
- Prior art keywords
- selenium
- layer
- rectifier
- cadmium sulphide
- sulphide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 title description 24
- 229910052711 selenium Inorganic materials 0.000 title description 24
- 239000011669 selenium Substances 0.000 title description 24
- CJOBVZJTOIVNNF-UHFFFAOYSA-N cadmium sulfide Chemical compound [Cd]=S CJOBVZJTOIVNNF-UHFFFAOYSA-N 0.000 description 14
- 229910052980 cadmium sulfide Inorganic materials 0.000 description 14
- 238000000576 coating method Methods 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000000903 blocking effect Effects 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 4
- 238000001704 evaporation Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000000151 deposition Methods 0.000 description 3
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- 229910052793 cadmium Inorganic materials 0.000 description 2
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- RPUCXGXPWYXBOD-UHFFFAOYSA-N Maytine Natural products CC(=O)OCC12C(CC3C(OC(C)=O)C1(OC3(C)C)C(C)(O)CC(OC(C)=O)C2OC(C)=O)OC(=O)c1cccnc1 RPUCXGXPWYXBOD-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- DPLVEEXVKBWGHE-UHFFFAOYSA-N potassium sulfide Chemical compound [S-2].[K+].[K+] DPLVEEXVKBWGHE-UHFFFAOYSA-N 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/06—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials
- H01L21/10—Preliminary treatment of the selenium or tellurium, its application to the foundation plate, or the subsequent treatment of the combination
- H01L21/105—Treatment of the surface of the selenium or tellurium layer after having been made conductive
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02367—Substrates
- H01L21/0237—Materials
- H01L21/02425—Conductive materials, e.g. metallic silicides
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02436—Intermediate layers between substrates and deposited layers
- H01L21/02439—Materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02518—Deposited layers
- H01L21/02521—Materials
- H01L21/02551—Group 12/16 materials
- H01L21/02557—Sulfides
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02612—Formation types
- H01L21/02617—Deposition types
- H01L21/02623—Liquid deposition
- H01L21/02625—Liquid deposition using melted materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02612—Formation types
- H01L21/02617—Deposition types
- H01L21/02631—Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/06—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials
- H01L21/10—Preliminary treatment of the selenium or tellurium, its application to the foundation plate, or the subsequent treatment of the combination
- H01L21/108—Provision of discrete insulating layers, i.e. non-genetic barrier layers
Definitions
- My invention relates to dry-contact rectifiers or light-sensitive devices and particularly to devices of this type which employ a layer of selenium.
- One object of my invention is to provide a selenium rectifier or light-sensitive device in which the surface of the selenium at which the rectification or photo-electric effect is produced is provided with a boundary layer which insures a high resistance to current flow in the nominally non-conductive direction when an alternating voltage is impressed upon it.
- a boundary layer which insures a high resistance to current flow in the nominally non-conductive direction when an alternating voltage is impressed upon it.
- Such a layer may be referred to as a blocking layer.
- Another object of my invention is to produce on a selenium layer a blocking layer which has a high resistance to current flow in the nominally non-conductive direction but which does not introduce a high resistance to current flow in the nominally conductive direction.
- Another object of my invention is to provide a selenium layer with a blocking layer which shall not undergo such chemical reaction during the practical use of the device incorporating it that the latter will change its electrical characteristics, or as it is sometimes termed will age, at a deleterious rate in service.
- Fig. 1 is an elevation and Fig. 2 a top view of a rectifier embodying the principles ofmy invention.
- the rectifier comprises a base-plate I which may comprise steel which has first been sand-blasted on the surface and thereafter nickel-plated.
- the plate I thus prepared is preferably provided with a central hole 2 by which it may be mounted upon a spindle provided with means for rapidly rotating it.
- the plate and spindle while in rotation are dipped into molten selenium and then withdrawn therefrom.
- the centrifugal force removes all of the selenium except a thin uniform layer 3 from the surface of the plate.
- the surface of the selenium is coated by evaporation and condensation with cadmium sulphide 4.
- the coating process may be carried out by heating cadmium sulphide inside an enclosure which is preferably evacuated to a pressure below about /40 of atmospheric. While the unit thus produced may tin. I prefer in accordance with the process described in my copending application Serial No. 509,817, filed November 10, 1943, now Patent No. 2,447,630, to apply the said contact layer first to the cadmium sulphide surface and thereafter to anneal the unit by heating it to the temperature of the order of C. for a suitable period, for example, for a time between six and sixteen hours.
- the unit rectifier when made in accordance with the process just described, may then be connected to electrical circuits in any of the standard connections for rectifier discs.
- the method of making a selenium rectifier which comprises coating a base-plate with selenium, depositing a. layer of cadmium sulphide by evaporation on the free surface of the selenium, producing a contact layer on the free surface of the cadmium sulphide and heating the resultant unit to a temperature of the order of 185 C. for a period of at least six hours.
- An-electrical circuit element comprising a 4 being coated at least in part with a layer'oi' m mm) cadmium.
- a rectifier comprising a base-plate having The following references are of record in the a coating of selenium with a coating oftgzdmium file of this patent: sulphide on its free surface and a con t layer .on the free surface of the cadmium sulphide. 5 UNITED STATES PATENTS 9. .A rectifier comprising a base-plate having Number Name Date a layer of selenium which has a coating of 2,121,603 Lotz June 21, 1938 cadmium sulphide on its free surface, the free 2,193,610 Wilson Mar. 12, 1940 surface of the cadmium sulphide being coated m 2,195,725 Hoppe Apr. 2, 1940 with cadmium. 1 2,221,596 Lorenz Nov. 12, 1940 2,227,827 Dubar Jan. 7, 1941 WAYNE E. BLACKBURN. 2,279,187 Thompson Apr. 7, 1942
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biotechnology (AREA)
- Electroplating Methods And Accessories (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
- Electroplating And Plating Baths Therefor (AREA)
- Thermistors And Varistors (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Description
NW, 15, 1949 w. E. BLACKBURN &
SELENIUM RECTIFIER Filed Dec. 15, 1943 C 07 jfiaamz'wrz 12 i 4 a 277/0222 z// 7720? m 3 SZQEZ WITNESSES: INVENTOR Wayne 5. Blue/{warn ATTORNEY Patented Nov. 15, 1949 SELENIUM RECTIFIER Wayne E. Blackburn, Wilkinsburg, Pa... assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 15, 1943, Serial No. 514,371
9 Claims. (Cl. 175-3.66)
My invention relates to dry-contact rectifiers or light-sensitive devices and particularly to devices of this type which employ a layer of selenium.
One object of my invention is to provide a selenium rectifier or light-sensitive device in which the surface of the selenium at which the rectification or photo-electric effect is produced is provided with a boundary layer which insures a high resistance to current flow in the nominally non-conductive direction when an alternating voltage is impressed upon it. Such a layer may be referred to as a blocking layer.
Another object of my invention is to produce on a selenium layer a blocking layer which has a high resistance to current flow in the nominally non-conductive direction but which does not introduce a high resistance to current flow in the nominally conductive direction.
Another object of my invention is to provide a selenium layer with a blocking layer which shall not undergo such chemical reaction during the practical use of the device incorporating it that the latter will change its electrical characteristics, or as it is sometimes termed will age, at a deleterious rate in service.
Other objects of my invention will become apparent upon reading the following description taken in connection with the drawing in which, Fig. 1 is an elevation and Fig. 2 a top view of a rectifier embodying the principles ofmy invention.
Referring in details to the drawing the rectifier comprises a base-plate I which may comprise steel which has first been sand-blasted on the surface and thereafter nickel-plated. The plate I thus prepared is preferably provided with a central hole 2 by which it may be mounted upon a spindle provided with means for rapidly rotating it. The plate and spindle while in rotation are dipped into molten selenium and then withdrawn therefrom. The centrifugal force removes all of the selenium except a thin uniform layer 3 from the surface of the plate. The surface of the selenium is coated by evaporation and condensation with cadmium sulphide 4. The coating process may be carried out by heating cadmium sulphide inside an enclosure which is preferably evacuated to a pressure below about /40 of atmospheric. While the unit thus produced may tin. I prefer in accordance with the process described in my copending application Serial No. 509,817, filed November 10, 1943, now Patent No. 2,447,630, to apply the said contact layer first to the cadmium sulphide surface and thereafter to anneal the unit by heating it to the temperature of the order of C. for a suitable period, for example, for a time between six and sixteen hours. The unit rectifier, when made in accordance with the process just described, may then be connected to electrical circuits in any of the standard connections for rectifier discs.
While I have described the application to the surface of the selenium as comprising cadmium sulphide, other metallic compounds of the sulphur family may be substituted therefor; for example, mercuric sulphide or potassium sulphide may be substituted.
I claim as my invention:
1. The method of forming a blocking layer on selenium which comprises producing thereon a layer of cadmium sulphide.
2. The method of producing an electric circuit element embodying selenium which comprises forming a surface of selenium and superposing thereon a layer of cadmium sulphide.
3. The method of producing ari electrical circuit element which comprises depositing by evaporation on a surface of amorphous selenium a layer of cadmium sulphide.
4. The method of making a selenium rectifier which comprises coating a base-plate with selenium, depositing a layer of cadmium sulphide by evaporation on the free surface of the selenium producing a contact layer on the free surface of the cadmium sulphide and heating the resultant unit to a temperature of the order of 185 C.
5. The method of making a selenium rectifier which comprises coating a base-plate with selenium, depositing a. layer of cadmium sulphide by evaporation on the free surface of the selenium, producing a contact layer on the free surface of the cadmium sulphide and heating the resultant unit to a temperature of the order of 185 C. for a period of at least six hours.
6. An-electrical circuit element comprising a 4 being coated at least in part with a layer'oi' m mm) cadmium.
8. A rectifier comprising a base-plate having The following references are of record in the a coating of selenium with a coating oftgzdmium file of this patent: sulphide on its free surface and a con t layer .on the free surface of the cadmium sulphide. 5 UNITED STATES PATENTS 9. .A rectifier comprising a base-plate having Number Name Date a layer of selenium which has a coating of 2,121,603 Lotz June 21, 1938 cadmium sulphide on its free surface, the free 2,193,610 Wilson Mar. 12, 1940 surface of the cadmium sulphide being coated m 2,195,725 Hoppe Apr. 2, 1940 with cadmium. 1 2,221,596 Lorenz Nov. 12, 1940 2,227,827 Dubar Jan. 7, 1941 WAYNE E. BLACKBURN. 2,279,187 Thompson Apr. 7, 1942
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL70500D NL70500C (en) | 1943-12-15 | ||
US514371A US2488369A (en) | 1943-12-15 | 1943-12-15 | Selenium rectifier |
GB24520/44A GB596585A (en) | 1943-12-15 | 1944-12-07 | Improvements in or relating to selenium rectifiers or light-sensitive devices |
CH248334D CH248334A (en) | 1943-12-15 | 1945-10-11 | Electrical organ with a selenium layer and method of manufacturing the same. |
FR988428D FR988428A (en) | 1943-12-15 | 1947-07-11 | Selenium rectifiers |
DEW1630A DE884847C (en) | 1943-12-15 | 1950-04-13 | Dry contact rectifier or light-sensitive element |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US514371A US2488369A (en) | 1943-12-15 | 1943-12-15 | Selenium rectifier |
Publications (1)
Publication Number | Publication Date |
---|---|
US2488369A true US2488369A (en) | 1949-11-15 |
Family
ID=24046859
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US514371A Expired - Lifetime US2488369A (en) | 1943-12-15 | 1943-12-15 | Selenium rectifier |
Country Status (6)
Country | Link |
---|---|
US (1) | US2488369A (en) |
CH (1) | CH248334A (en) |
DE (1) | DE884847C (en) |
FR (1) | FR988428A (en) |
GB (1) | GB596585A (en) |
NL (1) | NL70500C (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2871149A (en) * | 1955-05-02 | 1959-01-27 | Sprague Electric Co | Semiconductor method |
US2886434A (en) * | 1955-06-06 | 1959-05-12 | Horizons Inc | Protected photoconductive element and method of making same |
US3023121A (en) * | 1959-08-13 | 1962-02-27 | Robert L Dyar | Method of constructing abrasive coated cylinders |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE968580C (en) * | 1948-10-02 | 1958-03-06 | Standard Elektrik Ag | Process for the manufacture of dry rectifiers |
DE973817C (en) * | 1951-03-05 | 1960-06-15 | Licentia Gmbh | Method of manufacturing a dry rectifier |
US2901348A (en) * | 1953-03-17 | 1959-08-25 | Haloid Xerox Inc | Radiation sensitive photoconductive member |
US2853663A (en) * | 1954-07-08 | 1958-09-23 | Vickers Inc | Power transmission |
NL204284A (en) * | 1955-02-15 | |||
DE1034290B (en) * | 1956-02-07 | 1958-07-17 | Zeiss Jena Veb Carl | Process for increasing the sensitivity, in particular the ultra-red sensitivity, of selenium barrier cells sensitized for the ultra-red range |
DE1090768B (en) * | 1957-05-11 | 1960-10-13 | Licentia Gmbh | Process for the production of selenium dry rectifiers |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2121603A (en) * | 1936-05-30 | 1938-06-21 | Westinghouse Electric & Mfg Co | Method of producing selenium rectifiers |
US2193610A (en) * | 1938-02-17 | 1940-03-12 | Westinghouse Electric & Mfg Co | Selenium contact electrode |
US2195725A (en) * | 1937-11-01 | 1940-04-02 | Hermes Patentverwertungs Gmbh | Method of manufacturing selenium rectifiers |
US2221596A (en) * | 1938-01-22 | 1940-11-12 | Fides Gmbh | Method of manufacturing dry rectifiers |
US2227827A (en) * | 1938-09-21 | 1941-01-07 | Union Switch & Signal Co | Manufacture of devices presenting electrical asymmetric conductivity |
US2279187A (en) * | 1939-01-11 | 1942-04-07 | Union Switch & Signal Co | Alternating electric current rectifier of the selenium type |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB439774A (en) * | 1934-03-21 | 1935-12-13 | British Thomson Houston Co Ltd | Improvements relating to photo-electric cells and methods of manufacturing the same |
BE436627A (en) * | 1938-10-24 | |||
DE760089C (en) * | 1940-04-24 | 1954-08-16 | Siemens Schuckertwerke A G | Process for improving the blocking effect of selenium rectifiers |
DE640567C (en) * | 1966-09-08 | 1937-01-07 | Siemens Schuckertwerke Akt Ges | Dry plate rectifier |
-
0
- NL NL70500D patent/NL70500C/xx active
-
1943
- 1943-12-15 US US514371A patent/US2488369A/en not_active Expired - Lifetime
-
1944
- 1944-12-07 GB GB24520/44A patent/GB596585A/en not_active Expired
-
1945
- 1945-10-11 CH CH248334D patent/CH248334A/en unknown
-
1947
- 1947-07-11 FR FR988428D patent/FR988428A/en not_active Expired
-
1950
- 1950-04-13 DE DEW1630A patent/DE884847C/en not_active Expired
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2121603A (en) * | 1936-05-30 | 1938-06-21 | Westinghouse Electric & Mfg Co | Method of producing selenium rectifiers |
US2195725A (en) * | 1937-11-01 | 1940-04-02 | Hermes Patentverwertungs Gmbh | Method of manufacturing selenium rectifiers |
US2221596A (en) * | 1938-01-22 | 1940-11-12 | Fides Gmbh | Method of manufacturing dry rectifiers |
US2193610A (en) * | 1938-02-17 | 1940-03-12 | Westinghouse Electric & Mfg Co | Selenium contact electrode |
US2227827A (en) * | 1938-09-21 | 1941-01-07 | Union Switch & Signal Co | Manufacture of devices presenting electrical asymmetric conductivity |
US2279187A (en) * | 1939-01-11 | 1942-04-07 | Union Switch & Signal Co | Alternating electric current rectifier of the selenium type |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2871149A (en) * | 1955-05-02 | 1959-01-27 | Sprague Electric Co | Semiconductor method |
US2886434A (en) * | 1955-06-06 | 1959-05-12 | Horizons Inc | Protected photoconductive element and method of making same |
US3023121A (en) * | 1959-08-13 | 1962-02-27 | Robert L Dyar | Method of constructing abrasive coated cylinders |
Also Published As
Publication number | Publication date |
---|---|
GB596585A (en) | 1948-01-07 |
NL70500C (en) | 1900-01-01 |
DE884847C (en) | 1953-07-30 |
FR988428A (en) | 1951-08-27 |
CH248334A (en) | 1947-04-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2488369A (en) | Selenium rectifier | |
US2002221A (en) | Dry rectifier | |
US2479301A (en) | Selenium rectifier | |
US2189580A (en) | Method of making a photoelectric cell | |
US2496432A (en) | Selenium rectifier | |
US2279187A (en) | Alternating electric current rectifier of the selenium type | |
US1751363A (en) | Electric-current rectifier | |
US1866351A (en) | Rectification of alternating currents | |
US2524270A (en) | Selenium rectifier | |
US2215999A (en) | Selenium rectifier having an insulating layer | |
US2196830A (en) | Photoelectric cell | |
US2610386A (en) | Semiconductive cell | |
US2485589A (en) | Selenium rectifier and photocell | |
US2476800A (en) | Rectifier | |
US2479446A (en) | Method of manufacturing small current selenium rectifiers | |
US2554237A (en) | Rectifier | |
US2356094A (en) | Method of treating selenium elements | |
US2496692A (en) | Selenium rectifier | |
US1770839A (en) | Electric contact | |
US2473884A (en) | Contact means | |
US2229807A (en) | Method of manufacturing selenium rectifiers | |
US1924300A (en) | Copper oxide rectifier | |
US2555247A (en) | Semiconductive cell | |
US2447630A (en) | Method of making selenium rectifiers | |
US2749596A (en) | Method of making titanium dioxide rectifiers |