Selenium cells / The construction, care and use of selenium cells with special reference to the Fritts cell

Thomas William Benson

CHAPTER I Selenium, the Element

CHAPTER II Consideration of Cell Types and Their Characteristics

CHAPTER III The Construction of Fritts Selenium Cell

CHAPTER IV Testing and Maturing Selenium Cells

CHAPTER V Applications of Selenium Cells

CHAPTER VI The Care Of Selenium Cells

The cover image was created by the transcriber, and is placed in the public domain.

SELENIUM CELLS

THE CONSTRUCTION, CARE AND USE
OF SELENIUM CELLS WITH SPECIAL
REFERENCE TO THE FRITTS CELL

BY
THOS. W. BENSON

NEW YORK
SPON & CHAMBERLAIN, 120 Liberty Street
LONDON
E. & F. N. SPON, Limited, 57 Haymarket, S. W.
1919

APPRECIATIVELY
DEDICATED
TO
J. A. STELTZER

FOREWORD

The lack of definite information relative to the construction of selenium cells has led the writer to put in this form the results of some of his experiments. The method described was originated by Mr. C. E. Fritts but the apparatus used was developed by the writer.

Despite the fact that sensitive cells are very difficult to construct by the methods in vogue the use of apparatus described practically eliminates failures, the cells, almost without exception, being useful for one purpose or another.

This is by no means the last word on the subject. Many improvements are possible and have been pointed out in the text. Should these instructions but serve to interest others in the fascinating study they will have served their purpose.

Thos. W. Benson.

Philadelphia, Pa.

CONTENTS

PAGE
CHAPTER I
Selenium, the Element		1
	Discovery, Naming and Classification. Where Found and Method of Extraction. Three Forms, Amorphous, Vitreous and Metallic.
CHAPTER II
Consideration of Cell Types and Their Characteristics		5
	Factors in Design. Bildwell Cell. Application of Selenium and Annealing. Ruhmer Cell. Bell and Taintor Cell. Mercadier Cell. Gripenberg Cell. Theory of Operation.
CHAPTER III
The Construction of Fritts Selenium Cell		20
	Description of Hot Press. Accessories for Press. Other Apparatus Required and Supplies. Preparing Copper Plate. Applying Selenium. Treating in Hot Press. Application of Gold Foil. Assembling Cell.
CHAPTER IV
Testing and Maturing Selenium Cells		32
	Two States. Testing and Maturing Set. Accessories for Set. Construction of Rheostat Arm for Wheatstone Bridge. Measurement of Cells by Bridge Method. Tests for Light Sensitiveness. Proper Voltage. Classification of Cells. Testing for Polarization. Treating with A. C. Raising Resistance of Cells. Testing for Current Generation. Reconstruction of Useless Cells. Measurement of Cells by Substitution Method. Sealing Cells.
CHAPTER V
Applications of Selenium Cells		51
	Photometric Applications. Transmission of Speech Over Beams of Light. Automatic Control of Light Buoys and Isolated Lights. As Recorder of Sunlight. Astronomical Applications. Talking Pictures. The Phonoptican, How the Blind May Read by Sound. Controlling Mechanisms at a Distance. Electric Dog. Use in Cable Telegraphy. Burglar Alarm. Selenium Batteries, Current Generators. Telephonic Properties. Effect of Different Current Sources on Sensitiveness of Cells.
CHAPTER VI
The Care of Selenium Cells		62

LIST OF ILLUSTRATIONS

FIG.		PAGE
1.	Bildwell Cell	7
2.	Ruhmer Cell	10
3.	Bell and Taintor Cell	12
4.	Mercadier Cell	14
5.	Gripenberg Cell	15
6.	Fritts Cell	17
7.	Hot Press with Cell in Place	21
8.	Details of Hot Press (elevation)	22
8.	Details of Hot Press (plan)	22
9.	Platen for Cell; and Template for Applying Selenium	24
10.	Fiber Pieces for Enclosing Cell	26
11.	Mode of Assembling Cell	30
12.	Testing and Maturing Set	33
13.	Layout and Wiring Diagram of Testing Maturing Set	35
14.	Connections for Buzzer and Induction Coil to Produce Alternating Current	36
15.	Connections for Interior of Rheostat Box	38
16.	Circuit for Wheatstone Bridge Measurement	40
17.	Circuit for substitution Method of Measurement	47
18.	Showing Cell ready for Assembly with Four Complete Cells in background	49

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