The boy electrician

Front matter

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Copyright^?. _ma

COPYRIGHT DEPOSIT.

Introduction

Once upon a time, and this is a true tale, a boy had a whole rail¬ road system for a toy. The train ran automatically, propelled by tiny electric motors, the signals went up and down, the station was reached, a bell rang, the train moved on again and was off on its journey around many feet of track to come back over the old route.

The boy viewed his gift with raptured eyes, and then his face changed and he cried out in the bitterness of his disappointment: “But what do I do? ” The toy was so elaborate that the boy was left entirely out of the play. Of course he did not like it. His cry tells a long story.

The prime instinct of almost any boy at play is to make and to create . He will make things of such materials as he has at hand, and use the whole force of dream and fancy to create something out of nothing. The five-year-old will lay half a dozen wooden blocks to¬ gether with a spool on one end and tell you it is a steam train. And it is. He has both made and created an engine, which he sees but which you don’t, for the blocks and spool are only a symbol of his creation. Give his older brother a telephone receiver, some wire and bits of brass, and he will make a wireless telegraph outfit and listen to a steamship hundreds of miles away spell out its message to the shore.

The wireless outfit is not a symbol, but something that you can both hear and see in operation even though you may not understand the whispering of the dots and dashes. And as soon as the mystery of this modem wonder more firmly grips your imagination, you per-

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INTRODUCTION haps may come to realize that we are living more and more in the age of electricity and mechanism. Electricity propels our trains, lights our houses and streets, makes our clothes, cures our ills, warms us, cooks for us and performs an innumerable number of other tasks at the turning of a little switch. A mere list is impossible.

Almost every boy experiments at one time or another with elec¬ tricity and electrical apparatus. It is my purpose in writing this book to open this wonderland of science and present it in a manner which can be readily understood, and wherein a boy may “ do some¬ thing.” Of course there are other books with the same purport, but they do not accomplish their end. They are not practical. I can say this because as a boy I have read and studied them and they have fallen far short of teaching me or my companions the things that we were seeking to learn. If they have failed in this respect, they have done so perhaps not through any inability of the author, but from the fact that they have not been written from the boy’s standpoint. They tell what the author thought a boy ought to know but not what he really does want to know. The apparatus described therein is for the most part imaginary. The author thought it might be possible for a boy to build motors, telegraph instruments, etc., out of old bolts and tin cans, but he never tried to do so himself.

The apparatus and experiments that I have described have been constructed and carried out by boys. Their problems and their questions have been studied and remedied. I have tried to present practical matter considered wholly from a boy’s standpoint, and to show the young experimenter just what he can do with the tools and materials in his possession or not hard to obtain.

To the boy interested in science, a wide field is open. There is no better education for any boy than to begin at the bottom of the lad¬ der and climb the rungs of scientific knowledge, step by step. It

INTRODUCTION

Vll equips him with information which may prove of inestimable worth in an opportune moment.

New developments in science will never cease. Invention will follow invention. The whole structure of the radio art, the commermercial values of which now mount up to several billions of dollars, has been built since 1910.

There can be no boy who will follow exactly any directions given to him, or do exactly as he is told, of his own free will. He will “bolt” at the first opportunity. If forced or obliged to do as he is directed, his action will be accompanied by many a “why?” There¬ fore in presenting the following chapters I have not only told how to make the various motors, telegraphs, telephones, radio receivers, etc. but have also explained the principles of electricity upon which they depend for their operation, and how the same thing is accomplished in the every-day world. In giving directions or offering cautions, I have usually stated the reason for so doing, in the hope that this information may be a stimulant to the imagination of the young experimenter and a useful guide in enabling him to proceed along some of the strange roads on which he will surely go.

Alfred P., ,Morgan)

Upper Montclair, N. J.

Chapter I Page

Magnets and Magnetism..

The Discovery of the Magnet — The Origin of the Compass — Ex¬ periments with Magnetism — Artificial Magnets — Making a Magnet — Magnetic Poles — Magnetic Force — Compasses — Magnetic Sub¬ stances — Attraction through Bodies — Magnetic Induction — The Laws of Magnetic Attraction — Lines of Magnetic Force — The Mag¬ netic Circuit — The Earth a Great Magnet — Magnetic Dip — A Dipping Needle — The Uses of Magnets — Preserving a Magnet.

Chapter II

The Wonderful Amber — The First Observation of Electricity — Benjamin Franklin’s Famous Kite — Lightning and Electricity — Electrical Induction — Two Kinds of Electricity — Conductors and Insulators — Electrified Writing-Paper — A Surprise for the Cat — Frictional Electricity — Electroscopes — The Pith-Ball Electroscope —

The Gold-Leaf Electroscope — Positive and Negative Electricity —

The Electrophorus — An Electrical Frog-Pond.

Chapter III

A Cylinder Electric Machine — Selecting the Bottle — Mounting the Bottle — The Base — The “ Rubber ” — The Prime Conductor —

Using the Machine — The Wimshurst Machine — The Glass Plates —

The Sectors — The Bosses — The Frame — The Uprights — The

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Driving-Wheels — The Collectors — The Neutralizers — Experiments with an Electric Machine — The Leyden Jar — Igniting Gunpowder

— The Electric Umbrella — A Lightning Board — The Electric Dance

— The Electric Whirl — Lichtenberg’s Figures.

CHAPTER IV Cells and Batteries

Build your own Batteries first — The Voltaic Cell — How Electricity is made with Chemicals — A Simple Cell — Leclanche Cell — Polari¬ zation — Dry Cells — How to make a Dry Cell — Recharging Dry Cells — Wet Batteries — Carbon Plates — Battery Elements — Bi¬ chromate Batteries — Handling Acid — A Plunge Battery — The Edison - Lalande Cell — A Tomato-Can Battery — Secondary or Storage Batteries — Connecting Cells — Making a Storage Battery — The Plates — Forming the Plates — Charging a Storage Battery — Ampere Hours.

CHAPTER V Electro - Magnetism and Magnetic Induction

Oersted’s Experiment — The Magnetic Field about a Wire Carrying Current — Field of Force — The Iron Core — The Principle of an Electro - Magnet — Electro - Magnets — Handling Steel Rails with Electro-Magnets — Magnetic Induction.

CHAPTER VI Electrical Units

The Units of Electrical Measure — Measuring the Current — The Ampere — The Volt — Electro-motive Force — The Ohm — Ohm’s Law — The Watt — The Electrical Horse-power — The Kilowatt — The Coulomb — The Difference between Alternating and Direct Cur¬ rents — The Cycle — The Alternation — Frequency.

CHAPTER VII Electrical Appurtenances

Wires — Wire Sizes — Insulators — Binding-Posts — Switches and Cut-Outs — Home-made Switches — Fuses — Lightning-Arresters.

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Chapter VIII Page

Meters — A Simple Voltmeter and Ammeter — A Portable Volt¬ meter and Ammeter — Calibrating the Meters — Connecting the Meters — Galvanoscopes and Galvanometers — Simple Galvanoscopes — Astatic Galvanoscope — Astatic Galvanometer — How to Make a Wheatstone Bridge — Resistance-Coils — How to Use a Wheatstone Bridge for Measuring Resistance.

Chapter IX

How to Build an Electric Bell — An Electric Alarm — An Annun¬ ciator — Push-Buttons — Bell Systems — A Burglar Alarm.

Chapter X

The First Telegraph — The Principle of the Telegraph — The Key — The Sounder — How to Make a Simple Key and Sounder — Con¬ necting the Instruments — A Complete Telegraph Set — How to Build a Telegraph Relay — Connecting a Relay — How to Learn to Telegraph — The Alphabet — Operating.

CHAPTER XI Microphones — How to Hear a Fly’s Footstep — Telephones

The Principle of the Telephone — The Telephone Transmitter — The Telephone Receiver — How to Build a Telephone — Telephone Re¬ ceivers — A Home-made Telephone Receiver — A Home-made Tele¬ phone Transmitter — A Complete Telephone Instrument — A Desk- Stand Type of Telephone — A Telephone Induction Coil — Connect¬ ing the Telephones.

Chapter XII

A Medical Coil or Shocking Coil — Spark Coils — The Principle of the Spark Coil — Building a Spark Coil — The Core — The Primary

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— The Secondary —• Winding the Secondary — The Interrupter —

The Condenser — Finishing the Coil —• Experiments with a Spark Coil — Electrical Hands — Geissler Tubes — Ghost Light — Puncturing Paper — A Practical Joke — An Electrified Garbage-Can — Photo¬ graphing an Electric Discharge — Jacob’s Ladder — X-Rays — The Tube — The Fluoroscope — Using the Outfit.

Chapter XIII

How Alternating Current is Transmitted — An Alternating Current System — The Transformer — Step-Up Transformers — Step-Down Transformers — An Experimental Transformer —• The Core — The Windings —• Arranging the Switches — Connecting and Mounting the Transformer.

Chapter XIV

The Principle of Wireless Telegraphy — Wireless Waves — A Simple Transmitter — Waves in the Ether — The Action of the Receiving Station — How to Build Wireless Instruments — The Aerial — Erecting the Aerial —• The Ground Connection — The Receiving Apparatus — A Tuning Coil — Detectors — A Crystal Detector — “Cat-Whiskers” Detectors — The Fixed Condenser — Telephone Receivers — Connect¬ ing the Receiving Apparatus —■ The Continental Code — A Coherer Outfit — The Coherer — The Decoherer — Building a Relay—’Con¬ necting and Adjusting the Apparatus — The Transmitting Apparatus — The Spark Coil — Small Spark-Gaps.

Chapter XV

Principles of Radio Reception and Transmission — The “Edison Effect” —• The DeForest Audion — A Simple Audion Receiving Circuit — The Audion Amplifier Circuit — How to Build a Single Tube Single Control Regenerative Receiver — Parts and Materials — Variable Con¬ denser —Filament Rheostat —• The Vacuum Tube—The Batteries—The Coil — Assembling and Connecting — A One Stage Amplifier — How to Build a Four Tube Regenerative Receiver — Parts and Materials —• The Circuit Diagram—The Radio-Frequency Transformer — The Volume Control—The Jacks — The Loud Speaker—’Assembling the Receiver — Tuning the Receiver.

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Chapter XVI Page

The Principle of the Wireless Telephone — Experiments illustrating the Principle of the Wireless Telephone —• Building a Wireless Tele¬ phone — Making the Coils — The Strap-Key — Connecting and Operating the Apparatus.

Chapter XVII

Thomas Davenport —• The First Electric Motor — A Simple Electric Motor — The Simplex Motor —• The Armature ■—• Making the Field Magnet—’The Bearings—'The Commutator Core — The Base — Assembling the Motor—• Connections — How to Build a Larger Motor — Cutting out the Laminations — Winding the Motor.

Chapter XVIII

The Difficulties of Building a Dynamo — The Principle of the Alter¬ nator and the Direct-Current Dynamo — Making a Magneto into a Dynamo — A 10-Watt Dynamo —• The Field —• The Armature —

The Commutator—'The Windings — The Base — The Bearings —

The Brushes ■—• Assembling and Completing the Dynamo.

Chapter XIX

A Toy Railway Car — How to Make the Running Gear — Installing the Motor—-Testing the Car—-Making the Body — How to Make the Track —• Track Patterns — A Cross-over — A Rail Connector — Making the Car Reversible — A Track Bumper — A Design for a Rail¬ way Bridge —• A Design for a Railway Station.

Chapter XX

What it may be used for — Carbon Battery Lamps — Tungsten Battery Lamps—-Lamp Bases — Sockets and Receptacles—-The Wires used for Miniature Lighting — Switches — Batteries—Mul¬ tiple Wiring — Series Wiring — Three-way Wiring — Lamp Brackets — A Hanging Lamp — Small Dry Cells — An Electric Hand-Lantern — A Ruby Lantern — A Night Lamp — A Watch-Light — An Electric Scarf-Pin.

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