The purpose of this book is to aid the young experimenter in building and operating his own electrical apparatus and instruments. Every boy of now-a-days experiments with electricity and the right sort of book which furnishes him with ideas gets close to his heart. Of books upon electricity there is no end. That is granted. But there are very few practical books for the young experimenter who wishes to construct miscellaneous electrical apparatus for his own amusement and instruction which really amounts to something and which is worth his pains when the labor has been finished. This book is therefore offered as a volume of instruction for making all sorts of batteries, rectifiers, motors, etc., which are entirely out of the toy class and yet are not so elaborate that they cannot be easily constructed at home by the average boy who is willing to put a little care into his work. The materials required are such that they can he procured without any great expense. It has been planned to present the material in such a manner that it will aid the judgment of the young experimenter and assist him in developing his own ideas. Without exception, all of the apparatus described in the following pages has been actually constructed by the author, not only once but many times and put to a practical test before being embodied into the book. You may therefore be sure that if you follow the instructions carefully, that the result will in each case be a substantial piece of apparatus which is capable of fulfilling all of your expectations. The drawings have all been reproduced on a large scale and in almost every case the dimensions of even the smallest details have been given. Some of the apparatus has been described in the pages of the "Boys' Magazine" and since its publication the readers of that magazine have written to the author asking questions about the apparatus which have enabled him when rewriting the material for publication in book form to clear up many questions and further explain in a little more detail many of the problems which naturally occur to the boy who likes to build his own electrical devices. THE AUTHOR. PREFACE CHAPTER I. STATIC ELECTRICAL APPARATUS CHAPTER II. CELLS AND BATTERIES. The Voltaic Cell. Homemade Batteries. Battery Solutions or Electrolytes. Connecting Cells. Storage or Secondary Cells. An Experimental Storage Cell. A Homemade Storage Cell. Recharging and Caring for Storage Cells. CHAPTER III. HOW TO REDUCE THE 110 V. D.C. OR A.C. TO A LOWER VOLTAGE FOR EXPERIMENTAL PURPOSES. CHAPTER IV. HOW AN ALTERNATING CURRENT MAY BE CHANGED INTO DIRECT CURRENT BY MEANS OF AN ELECTROLYTIC RECTIFIER. CHAPTER V. HOW TO BUILD A STEP-DOWN TRANSFORMER FOR REDUCING THE 110 VOLT A. C. FOR EXPERIMENTAL PURPOSES. CHAPTER VI. ELECTRIC MEASURING INSTRUMENTS Galvanometers, Ammeters, Voltmeters. How to Make a Galvanometer. The Construction of Ammeters and Voltmeters. CHAPTER VII. CURRENT CONTROL DEVICES. How to Make a Pole Changing Switch or Current Reverses How to Reverse a Small Motor. How to Make a Small Battery Rheostat for Regulating the Speed of Small Motors, Etc. CHAPTER VIII. HOW TO MAKE A TELEGRAPH KEY AND SOUNDER AND INSTALL A TELEGRAPH LINE. CHAPTER IX. HOW TO MAKE AND INSTALL A TELEPHONE. CHAPTER X. MEDICAL COILS AND SHOCKING COILS. CHAPTER XI. THE CONSTRUCTION OF SPARK COILS. Experiment 1—An Imitation Gassiot's Cascade. Experiment 2—A Ghostly Light Experiment 3—Lighting Geissler Tubes. Experiment 4—Flickering Light. Experiment 5—Rotating a Geissler Tube. Experiment 6—Fluorescent Writing. Experiment 7—An Electric Bomb. Experiment 8—Electrifying the Garbage Can. Experiment 9—How to Make an Electric Spark Photograph Itself. CHAPTER XII. HOW TO MAKE A DYNAMO-MOTOR CHAPTER XIII. AN ELECTRIC BATTERY MOTOR. CHAPTER XIV. HOW TO BUILD AN ELECTRIC ENGINE. CHAPTER XV. MINIATURE BATTERY LIGHTING. CHAPTER XVI. COHERER OUTFITS FOR WIRELESS TELEGRAPHY. CHAPTER XVII. HOW TO BUILD A TESLA HIGH FREQUENCY COIL. CHAPTER XVIII. AN EXPERIMENTAL WIRELESS TELEPHONE. CHAPTER XIX. MISCELLANEOUS EXPERIMENTS AND APPARATUS. - FIG. 1.—A simple Wimshurst Machine which any boy can easily make. P P, Plates; BR, Neutralizes; C R, Collectors; DR, Discharge Rods; J J, Leyden Jars; H H, Insulating Handles; C, Crank; U, Upright; B, Belt.
- FIG. 2.—The plates for the Static Machine are made of hard rubber and are 7 inches in diameter. Each plate carries sixteen tinfoil sectors.
- FIG. 3.—The details of the Tinfoil Sector. Sixteen are required for each plate. They are stuck to the plates with shellac.
- FIG. 4.—Details of the Grooved Pulley, attached to each plate. The Pulleys are turned out of wood.
- FIG. 5.—The base of the Wimshurst Machine. All woodwork about the machine should be carefully dried and then shellaced so that it cannot absorb any moisture.
- FIG. 6.—Details of one of the Uprights which support the Plates, Driving Pulleys, etc. These, being made of wood, should also be dried and shellaced so that they cannot absorb moisture.
- FIG. 7.—Showing the Two Uprights in position on the Base.
- FIG. 8.—The Driving Pulleys. These are turned out of wood and mounted on a shaft having a Crank at one end.
- FIG. 9.—The Crank is bent out of a piece of 3/16 rod, 7 inches long, into the shape shown.
- FIG. 10.—The Collector with the Discharge Rods, etc, in position. A is the Brass Ball forming one terminal of the gap across which the sparks jump. B is another Brass Ball screwed onto the end of the Collector Rod and having a hole in it, through which the Discharge Rod slips. CC are two threaded Washers used to clamp the Discharge Rod in place.
- FIG. 11.—Showing how Binding Posts may be substituted for Round Balls on the Collector Rods.
- FIG. 12.—Details of the Discharger Rods.
- FIG. 13.—The Supporting Bar upon which the Collector Rods are mounted. Made of hard rubber so as to be a perfect Insulator.
- FIG. 14.—The Neutralizers. Two are required. They are bent out of Brass Rod and fitted with a Tinsel Tuft at each end. The centre piece upon which the Rod is mounted should be of Hard Rubber.
- FIG. 15.—Details of the Leyden Jars. They are simply small Test Tubes, coated inside and outside with tinfoil for about two-thirds their height and fitted with a Brass Rod connected with the inside coating.
- FIG. 16.—A Large Leyden Jar for experimental purposes.
- FIG. 17.—Showing how to Discharge a Leyden Jar with a curved piece of stiff wire fitted to a Wooden Handle.
- FIG. 18.—The "Lightning Board" is simply a Strip of Glass covered with small Tinfoil Squares. It may be insulated by mounting on a Bottle. The two Wires attached to the wide Tinfoil Strips at the ends of the "Board" are for connection to the Static Machine or Leyden Jar.
- FIG. 19.—A very pretty effect can be produced by arranging small tinfoil strips on the Glass in a Pattern. Each strip should be separated from the other just far enough for a Spark to pass.
- FIG. 20.—A very pretty design made by arranging the Strips in the form of a Seven-pointed Star. Flowers, initials or almost any pattern may be made in the same way.
- FIG. 21.—The Electric Parasol. The upper right-hand corner shows a piece of Tissue Paper cut into Strips. (1) Is the apparatus before the Tissue Paper is fastened to the Cork. (2) Shows the completed "Parasol" and (3), the Parasol when connected to the machine and the latter is set in operation.
- FIG. 22.—Electric Birds. The Birds are made of Tissue Paper and should be about the size and shape shown in the lower right-hand corner of the illustration above.
- FIG. 23.—Electric Acrobats. The Acrobats are made of paper. The little figure in the upper right-hand part of the illustration is the proper size.
- FIG. 24.—The Electric Mortar. C is the Mortar, P the Powder, B a Small Ball and W W the two Wires between which the Spark igniting the powder takes place.
- FIG. 25.—An Electric Whirligig.
- FIG. 26.—A Voltaic Cell. A Voltaic Cell consists of a Strip of Copper and a Strip of Zinc immersed in a dilute solution of Sulphuric Acid.
- FIG. 27.—Ordinary Jelly Glasses, Tumblers, Fruit Jars, etc, make good Jars for small cells by cutting off the tops.
- FIG. 28.—A Simple Home-made Cell.
- FIG. 29.—A Home-made Battery having two Carbon Plates with a Zinc Rod between.
- FIG. 30.—The Elements for a Simple Home-made Cell composed of two Carbon Rods and one Zinc Rod clamped between two Wooden Strips.
- FIG. 31.—Four Carbon Rods and one Zinc Rod arranged to form the Elements of a Cell.
- FIG. 32.—A Battery of Three Cells arranged so that they can all be lifted out of the solution at once.
- FIG. 33.—Showing how Cells are arranged when they are connected in Series. The Voltage of Six Dry Cells connected in series as above would be approximately 6 x 1.5 or 9 Volts.
- FIG. 34.—Showing Six Dry Cells connected in Multiple. The Voltage of such an arrangement would only be 1.5, but the Amperage available would be six times that possible from Cells connected as in Figure 33.
- FIG. 35.—Showing how to connect a Battery of Cells in Series-Multiple.
- FIG. 36.—Battery Connectors like that shown above can be obtained for 1 1/2 cents each and will be found to be very handy.
- FIG. 37.—A Simple Experimental Storage Battery consisting of two Lead Plates immersed in Dilute Sulphuric Acid.
- FIG. 38.—Showing how to charge a Simple Storage Cell composed of two Lead Plates immersed in Sulphuric Acid by connecting it to two Bichromate of Potash Cells.
- FIG. 39.—Showing how the Plates for a Storage Cell may be made from Sheet Lead by boring it full of holes and filling with paste.
- FIG. 40.—A set of three Plates composed of One Positive and Three Negatives assembled to form a Cell.
- FIG. 41.—Glass and Rubber Storage Cell Jars which are on the market for the Electrical Experimenter and may be purchased very reasonably.
- FIG. 42.—An empty Storage Cell Grid and also a Pasted Plate both of which are on the market for experimenters who wish to build their own Cells.
- FIG. 43.—Two Negative Plates "burned" together and the Connecting Lug used.
- FIG. 44.—The Elements of a Storage Cell composed of two Negative Plates and one Positive Plate in their proper position.
- FIG. 45.—Three different sizes of Storage Cells which may be purchased ready made or built by the experimenter out of prepared materials as explained.
- FIG. 46.—A Hydrometer for preparing and testing the Acid Solution for Storage Batteries.
- FIG. 47.—The proper way of Recharging Storage Cells from the 110 Volts D. C. Supply in series with a set of Lamps.
- FIG. 48.—A Lamp Bank consisting of a Set of 110-Volt Lamps connected Multiple and arranged to be placed in series with any device it is desired to use on the 110-Volt Current.
- FIG. 49.—A Single Cell of Electrolytic Rectifier.
- FIG. 50.—An Electrode cut out of Sheet Metal. The top is bent over at right angles and drilled so that it can be mounted on the underside of the cover.
- FIG 51.—A Cast Electrode will last much longer than one cut from Sheet Metal. Cast Electrodes like that above are on the market and can be purchased very reasonably.
- FIG. 52.—A completed single Cell Rectifier. The right hand sketch shows how the Electrodes are mounted on the underside of the cover.
- FIG. 53.—A Diagram showing how a Rectifier cuts off one-half of the Alternating Current Wave and changes it into Pulsating Direct Current.
- FIG. 54.—Circuit showing how a Single Cell of Rectifier should be connected in series with a Lamp Bank to Recharge a Storage Cell. A is the Aluminum Plate and L the Lead or Iron Plate.
- FIG. 55.—Diagram showing the Difference in Current after it has been passed through a Single Cell or Rectifier and after passing through a Four-Cell Rectifier.
- FIG. 56.—Diagram showing how a Four-Cell Rectifier is connected. The Alternating Current Source is connected to C and D. The Direct Current is taken off at A and B. The Electrodes marked A, A, A, A are the Aluminum Electrodes. L, L, L, L may be Lead or Iron.
- FIG. 57—A Complete Four-Cell Rectifier connected together and Mounted in a Tray.
- FIG. 58.—Details of the two different Pieces of Sheet Iron used in building up the Core. Sufficient of each piece are required to form a pile of each three-quarters of an inch thick.
- FIG. 59.—The Method used in piling up the Strips to Assemble the Core.
- FIG. 60.—Assembly of the Core.
- FIG. 61.—Details of the Primary and Secondary Windings.
- FIG. 62.—Showing the Core completely assembled with the Primary and Secondary in position. P, P are the Primary Terminals. 1, 2 and 3 are the Secondary Terminals.
- FIG. 63.—The Step-down Transformer mounted on a Wooden Base.
- FIG. 64.—A detailed Drawing showing how the Sides of the Case are formed by bending a long strip of Sheet Iron at four points.
- FIG. 65.—Details of the Top and Bottom of the Case.
- FIG. 66.—The completed Transformer.
- FIG. 67.—A Simple Galvanometer.
- FIG. 68.—Details of the Bobbin.
- FIG. 69.—Details of the Armature, Bearings and Pointer.
- FIG. 70.—A complete Voltmeter having the Scale at the top.
- FIG. 71—An Ammeter so constructed that the Scale is at the bottom.
- FIG. 72.—Showing how the Armature, Shaft and Pointer are assembled for a Meter having the Scale at the bottom.
- FIG. 73.—Details of the Wooden Parts which form the Case.
- FIG. 74.—Showing how the Apparatus is arranged and connected for calibrating the Ammeter.
- FIG. 75.—Showing how the Apparatus is arranged and connected for calibrating the Voltmeter.
- FIG. 76.—A Pole changing Switch for reversing Small Motors or the direction of an Electric Current.
- FIG. 77.—Top view of a small Battery Rheostat
- FIG. 78.—Details of the Rheostat Base. The lower part of the illustration is a cross section.
- FIG. 79.—Looking at the Base from the bottom showing the grooves in which the Wires are laid.
- FIG. 80.—The German-silver Resistance Wire is wound around a Fibre Strip.
- FIG. 81.—The Lever, Knob, Binding Posts, etc.
- FIG. 82.—The completed Rheostat.
- FIG. 83.—Key Frame.
- FIG. 84.—Sounder Frame.
- FIG. 85.—The Electro Magnets.
- FIG. 86—The Sounder Armature.
- FIG. 87.—Sounder Frame with Lever in Position.
- FIG. 88.—Top View of Completed Instrument
- FIG. 89.—Side View of Key.
- FIG. 90.—Key and Circuit Closing Levers.
- FIG. 91.—American Morse Code.
- FIG. 92.—Circuit for Two Instruments.
- FIG. 93.—The Wooden Back for the Telephone.
- FIG. 94.—The Complete Telephone.
- FIG. 95.—Details of the Receiver Hook.
- FIG. 96.—Showing how the Push Button is arranged.
- FIG. 97.—Circuit showing how to connect two Telephone Stations to the Line.
- FIG. 98.—Bobbin for Medical Coil.
- FIG. 99.—Bobbin with Winding.
- FIG. 100.—Construction of the Core.
- FIG. 101.—Vibrator Parts and Core Cap.
- FIG. 102.—Regulator Tube.
- FIG. 103.—The Base with Location of Holes.
- FIG. 104.—Top View of Finished Coil.
- FIG. 105.—Side View of Completed Coil.
- FIG. 106.—Vibrator Parts.
- FIGS. 107 and 108.—Two Types of Handles.
- FIG. 109.—Induction or Spark Coil.
- FIG. 110.—The Primary and Core.
- FIG. 111.—The Secondary Winding.
- FIG. 112.—The Fixed Condenser.
- FIG. 113.—Details of the Wooden Coil Heads.
- FIG. 114.—Details of the Wooden Base.
- FIG. 115.—Details of the Interrupter. The Spring and Standard for the One inch coil should be made one-quarter of an inch longer.
- FIG. 116.—The tube.
- FIG. 117.—The Bridge.
- FIG. 118.—Section of the Spark Coil showing the arrangement of the Parts.
- FIG. 119.—End View of the Complete Coil.
- FIG. 120.—Side View of the Completed Coil.
- FIG. 121.—Diagram of Connections.
- FIG. 122.—Perspective view of Coil showing names of the various parts.
- FIG. 123—Front view of the Field Casting.
- FIG. 124.—Side elevation of the Field Casting.
- FIG. 125.—Details of the Armature.
- FIG. 126.—The Commutator.
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