The "How-to-do-it" Books

ELECTRICITY FOR BOYS

Fig. 1. WORK BENCH

THE "HOW-TO-DO-IT" BOOKS ELECTRICITY FOR BOYS A working guide, in the successive steps of electricity, described in simple terms WITH MANY ORIGINAL ILLUSTRATIONS By J. S. ZERBE, M.E. AUTHOR OF CARPENTRY FOR BOYSPRACTICAL MECHANICS FOR BOYS THE NEW YORK BOOK COMPANY New York

Copyright, 1914, by THE NEW YORK BOOK COMPANY

CONTENTS

Introductory Page 1

I. Electricity Considered. Brief Historical Events Page 5

The Study of Electricity. First Historical Accounts. Bottling Electricity. Discovery of Galvanic Electricity. Electro-motive Force. Measuring Instruments. Rapidity of Modern Progress. How to Acquire the Vast Knowledge. The Means Employed.

II. What Tools and Apparatus are Needed Page 11

Preparing the Workshop. Uses of Our Workshop. What to Build. What to Learn. Uses of the Electrical Devices. Tools. Magnet-winding Reel.

III. Magnets, Coils, Armatures, Etc. Page 18

The Two Kinds of Magnets. Permanent Magnets. Electro-Magnets. Magnetism. Materials for Magnets. Non-magnetic Material. Action of a Second Magnet. What North and South Pole Mean. Repulsion and Attraction. Positives and Negatives. Magnetic Lines of Force. The Earth as a Magnet. Why the Compass Points North and South. Peculiarity of a Magnet. Action of the Electro-Magnet. Exterior Magnetic Influence Around a Wires Carrying a Current. Parallel Wires.

IV. Frictional, Voltaic or Galvanic and Electro-magnetic Electricity Page 29

Three Electrical Sources. Frictional Electricity. Leyden Jar. Voltaic or Galvanic Electricity. Voltaic Pile; How Made. Plus and Minus Signs. The Common Primary Cell. Battery Resistance. Electrolyte and Current. Electro-magnetic Electricity. Magnetic Radiation. Different Kinds of Dynamos. Direct Current Dynamos. Simple Magnet Construction. How to Wind. The Dynamo Fields. The Armature. Armature Windings. Mounting the Armature. The Commutator. Commutator Brushes. Dynamo Windings. The Field. Series-wound Field. Shunt-wound. Compound-wound.

V. How to Detect and Measure Electricity Page 49

Measuring Instruments. The Detector. Direction of Current. Simple Current Detector. How to Place the Detector. Different Ways to Measure a Current. The Sulphuric Acid Voltameter. The Copper Voltameter. The Galvanoscope Electro-magnetic Method. The Calorimeter. The Light Method. The Preferred Method. How to Make a Sulphuric Acid Voltameter. How to Make a Copper Voltameter. Objections to the Calorimeter.

VI. Volts, Amperes, Ohms and Watts Page 60

Understanding Terms. Intensity and Quantity. Voltage. Amperage Meaning of Watts and Kilowatt. A Standard of Measurement. The Ampere Standard. The Voltage Standard. The Ohm. Calculating the Voltage.

VII. Push Buttons, Switches, Annunciators, Bells and Like Apparatus Page 65

Simple Switches. A Two-Pole Switch. Double-Pole Switch. Sliding Switch. Reversing Switch. Push Buttons. Electric Bells. How Made. How Operated. Annunciators. Burglar Alarm. Wire Circuiting. Circuiting System with Two Bells and Push Buttons. The Push Buttons, Annunciators and Bells. Wiring Up a House.

VIII. Accumulators, Storage or Secondary Batteries Page 82

Storing Up Electricity. The Accumulator. Accumulator Plates. The Grid. The Negative Pole. Connecting Up the Plates. Charging the Cells. The Initial Charge. The Charging Current.

IX. The Telegraph Page 90

Mechanism in Telegraph Circuit. The Sending Key. The Sounder. Connecting Up the Key and Sounder. Two Stations in Circuit. The Double Click. Illustrating the Dot and the Dash. The Morse Telegraph Code. Example in Use.

X. High-tension Apparatus, Condensers, Etc. Page 98

Induction. Low and High Tension. Elastic Property of Electricity. The Condenser. Connecting up a Condenser. The Interrupter. Uses of High-tension Coils.

XI. Wireless Telegraphy Page 104

Telegraphing Without Wires. Surging Character of High-tension Currents. The Coherer. How Made. The Decoherer. The Sending Apparatus. The Receiving Apparatus. How the Circuits are Formed.

XII. The Telephone Page 110

Vibrations. The Acoustic Telephone. Sound Waves. Hearing Electricity. The Diaphragm in a Magnetic Field. A Simple Telephone Circuit. How to Make a Telephone. Telephone Connections. Complete Installation. The Microphone. Light Contact Points. How to Make a Microphone. Microphone, the Father of the Transmitter. Automatic Cut-outs for Telephones. Complete Circuiting with Transmitters.

XIII. Electrolysis, Water Purification, Electroplating Page 123

Decomposing Liquids. Making Hydrogen and Oxygen. Purifying Water. Rust. Oxygen as a Purifier. Composition of Water. Common Air Not a Good Purifier. Pure Oxygen a Water Purifier. The Use of Hydrogen in Purification. Aluminum Electrodes. Electric Hand Purifier. Purification and Separation of Metals. Electroplating. Plating Iron with Copper. Direction of Current.

XIV. Electric Heating. Thermo-Electricity Page 135

Generating Heat in a Wire. Resistance of Substances. Signs of Connectors. Comparison of Metals. A Simple Electric Heater. How to Arrange for Quantity of Current Used. An Electric Iron. Thermo-Electricity Converting Heat Directly into Electricity Metals. Electric, Positive, Negative. Thermo-electric Coupler.

XV. Alternating Currents, Choking Coil, Transformer Page 145

Direct Current. Alternating Current. The Magnetic Field. Action of a Magnetized Wire. The Movement of a Current in a Charged Wire. Current Reversing Itself. Self-Induction. Brushes in a Direct Current Dynamo: Alternating, Positive and Negative Poles. How an Alternating Current Dynamo is Made. The Windings. The Armature Wires. Choking Coils. The Transformer. How the Voltage is Determined. Voltage and Amperage in Transformers.

XVI. Electric Lighting Page 161

Early conditions. Fuels. Reversibility of Dynamo. Electric arc. Mechanism to maintain the arc. Resistance coil. Parallel carbons for making arc. Series current. Incandescent system. Multiple circuit. Subdivision of electric light. The filament. The glass bulb. Metallic filaments. Vapor lamps. Directions for improvements. Heat in electric lighting. Curious superstitions concerning electricity. Magnetism. Amber. Discovery of the properties of a magnet. Electricity in mountain regions. Early beliefs as to magnetism and electricity. The lightning rod. Protests against using it. Pliny's explanation of electricity.

XVII. Power, and Various Other Electrical Manifestations Page 175

Early beliefs concerning the dynamo. Experiments with magnets. Physical action of dynamo and motor. Electrical influence in windings. Comparing motor and dynamo. How the current acts in a dynamo. Its force in a motor. Loss in power transmission. The four ways in which power is dissipated. Disadvantages of electric power. Its advantages. Transmission of energy. High voltages. The transformer. Step-down transformers. Electric furnaces. Welding by electricity. Merging the particles of the joined ends.

XVIII. X-Ray, Radium and the Like Page 184

The camera and the eye. Actinic rays. Hertzian waves. High-tension apparatus. Vacuum tubes. Character of the ultra-violet rays. How distinguished. The infra-red rays. Their uses. X-rays not capable of reflection. Not subject to refraction. Transmission through opaque substances. Reducing rates of vibration. Radium. Radio-activity. Radio-active materials. Pitchblende. A new form of energy. Electrical source. Healing power. Problems for scientists.

Glossary of Words Used in the Text Page 189

Index Page 207

LIST OF ILLUSTRATIONS

1. Work bench Frontispiece

PAGE

2. Top of magnet-winding reel 14

3. Side of magnet-winding reel 14

4. Journal block 15

5. Plain magnet bar 19

6. Severed magnet 20

7. Reversed magnets 21

8. Horseshoe magnet 22

9. Earth's magnetic lines 23

10. Two permanent magnets 24

11. Magnets in earth's magnetic field 24

12. Armatures for magnets 25

13. Magnetized field 26

14. Magnetized bar 26

15. Direction of current 27

16. Direction of induction current 28

17. Frictional-electricity machine 30

18. Leyden jar 32

19. Galvanic electricity. Crown of cups 33

20. Voltaic electricity 34

21. Primary battery 36

22. Dynamo field and pole piece 39

23. Base and fields assembled 41

24. Details of the armature, core 42

25. Details of the armature, body 42

26. Armature Journals 43

27. Commutator 43

28. End view of armature, mounted 44

29. Top view of armature on base 45

30. Field winding 47

31. Series-wound 47

32. Shunt-wound 48

33. Compound-wound 48

34. Compass magnet, swing to the right 50

35. Magnetic compass 50

36. Magnet, swing to the left 50

37. Indicating direction of current 51

38. The bridge of the detector 52

39. Details of detector 53

40. Cross-section of detector 54

41. Acid voltameter 56

42. Copper voltameter 56

43. Two-pole switch 66

44. Double-pole switch 66

45. Sliding switch 67

46. Rheostat form of switch 68

47. Reversing switch 69

48. Push button 70

49. Electric bell 71

50. Armature of electric bell 72

51. Vertical section of annunciator 72

52. Front view of annunciator 72

53. Horizontal section of annunciator 72

54. Front plate of annunciator 72

55. Alarm switch on window 76

56. Burglar alarm on window 76

57. Burglar alarm contact 77

58. Neutral position of contact 78

59. Circuiting for electric bell 79

60. Annunciators in circuit 80

61. Wiring system for a house 80

62. Accumulator grids 83

63. Assemblage of accumulator grids 85

64. Connecting up storage battery in series 87

65. Parallel series 88

66. Charging circuit 88

67. Telegraph sending key 91

68. Telegraph sounder 92

69. A telegraph circuit 94

70. Induction coil and circuit 99

71. Illustrating elasticity 100

72. Condenser 101

73. High-tension circuit 102

74. Current interrupter 103

75. Wireless-telegraphy coherer 105

76. Wireless sending-apparatus 107

77. Wireless receiving-apparatus 108

78. Acoustic telephone 111

79. Illustrating vibrations 111

80. The magnetic field 112

81. Section of telephone receiver 114

82. The magnet and receiver head 115

83. Simple telephone connection 116

84. Telephone stations in circuit 117

85. Illustrating light contact points 118

86. The microphone 119

87. The transmitter 119

88. Complete telephone circuit 121

89. Device for making hydrogen and oxygen 124

90. Electric-water purifier 127

91. Portable electric purifier 129

92. Section of positive plate 130

93. Section of negative plate 130

94. Positive and negative in position 130

95. Form of the insulator 130

96. Simple electric heater 137

97. Side view of resistance device 139

98. Top view of resistance device 139

99. Plan view of electric iron 140

100. Section of electric iron 141

101. Thermo-electric couple 143

102. Cutting a magnetic field 146

103. Alternations, first position 148

104. Alternations, second position 148

105. Alternations, third position 148

106. Alternations, fourth position 148

107. Increasing alternations, first view 149

108. Increasing alternations, second view 149

109. Connection of alternating dynamo armature 150

110. Direct current dynamo 151

111. Circuit wires in direct current dynamo 152

112. Alternating polarity lines 154

113. Alternating current dynamo 155

114. Choking coil 157

115. A transformer 158

116. Parallel carbons 164

117. Arc-lighting circuit 165

118. Interrupted conductor 166

119. Incandescent circuit 167

120. Magnetic action in dynamo, 1st 177

121. Magnetic action in dynamo, 2d 177

122. Magnetic action in dynamo, 3d 178

123. Magnetic action in dynamo, 4th 178

124. Magnetic action in motor, 1st 179

125. Magnetic action in motor, 2d 179

126. Magnetic action in motor, 3d 180

127. Magnetic action in motor, 4th 180