How Two Boys Made Their Own Electrical Apparatus Containing Com

The work-bench may be made of an old kitchen table, or of a strong, large box. The tool chest may be made of any clean box about the size of a soap box. Shelves can be made by s...

_160. Current Detectors; Galvanometers._ When a wire carrying a current of sufficient strength is properly brought near a magnetic needle, the latter will be deflected from its...

_192. Telegraph Keys._ Fig. 92. Telegraph keys are merely pieces of apparatus by which the circuit can be conveniently and rapidly opened or closed at the will of the operator....

_249. An Electric Motor_ is really a machine. If it be supplied with a proper current of electricity, its armature will revolve; and, if a pulley or wheel be fastened to the rev...

_134. Induction Coils_, or shocking coils, are rather expensive to buy, and altogether too complicated for boys to make by the methods usually given in books. The method here gi...

_1. Carbon-Zinc Cell._ Fig. 1. If you have some rubber bands you can quickly make a cell out of rods of zinc and carbon. The rods are kept apart by putting a band, B, around eac...

_107. Electro-Magnets_ are absolutely necessary in the construction of most pieces of electrical apparatus. There are several ways of making them at home. To quickly make a good...

_34. For Annealing and Hardening Steel._ (See text-book for reasons why some parts of electrical apparatus should be made of hard steel, while other parts should be made of soft...

_213. Electric Buzzer._ Fig. 100. A buzzer is, in construction, very similar to an electric bell; in fact, you will have a buzzer by removing the bell from any ordinary electric...

_94. Yokes_ are used to fasten two straight electro-magnets together to form a horseshoe electro-magnet. The reasons for using them should be understood. Soft iron should be use...

_81. Magnetic Needles and Compasses_ consist chiefly of a short bar-magnet. When used to tell the directions, north, east, etc., the apparatus is generally called a compass. Whe...

_21. Sulphuric Acid._ THIS ACID MUST BE HANDLED WITH GREAT CARE, as it (the concentrated) is very strong, and will burn the hands, eat holes in clothing, carpets, etc.; it will...

_57. Binding-Posts_ are used to make connections between two pieces of apparatus, between two or more wires, between a wire and any apparatus, etc., etc. They are used simply fo...

_224. Commutators and Current Reversers_ are useful in some experiments, as, for example, those with tangent galvanometers (App. 116, 117), in which readings are made with the c...

_272. Graduated Circles._ Fig. 123. For compasses (App. 67), and for use in connection with tangent galvanometers (App. 116), a graduated circle is necessary. Fig. 123 is a redu...

_127. Winder._ Fig. 68. In case you do not have any means of making a smooth hole for the "bearings" of the winders of App. 93 and 94, you can use a spool for the purpose. B is...

_236. Static or Frictional Electricity._ There are many interesting and instructive experiments in this branch of electricity. All that can be done here is to explain a few piec...

_52. Switches, Cut-Outs._ Where apparatus is to be used frequently, such as for telephone and telegraph lines, it pays to make your switches, etc., carefully. The use of these s...

_70. Permanent Magnets_ may be made in many ways and from many different kinds of steel. The steel used for needles, watch and clock springs, files, cutting tools, etc., is gene...

_154. Contact Breakers; Current Interrupters._ It is often necessary to make and break the electric current at frequent intervals. This can be done by an ordinary key (App. 118)...

_230. Resistance Coils._ Fig. 105. For experiments in resistance (See text-book), a set of standard resistances is necessary. There are many ways in which the resistances may be...