Things a Boy Should Know about Electricity (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ... coil. The primary coil is wound on a bolt which serves as the core, and on this coil is wound the secondary which Fi consists of many turns of fine wire. The wires from a battery should be joined to bindingposts W and X, and the handles, from which the shock is felt, to Y and Z. Fig. 103 shows the details of the interrupter. If the current from a cell enters at W, it will pass through the primary coil and out at X, after going through 5, R, F, S I, B, E and C. The instant the current passes, the bolt becomes magnetized; this attracts A, which pulls B away from the end of SI, thus automatically opening the circuit. B at once springs back to its former position against S I, as A is no longer attracted; the circuit being closed, the operation is rapidly repeated. A condenser is usually connected to commercial forms. It is placed under the wood-work and decreases sparking at the interrupter. (See "Apparatus Book," Chapter XI., for home-made induction coils.) Fig. 104 shows one form of coil. The battery wires are joined to the binding-posts at the left. The secondary coil ends in two rods, and the spark jumps from one to the other. The interrupter and a switch are shown at the left. Fig. 105 shows a small coil for medical purposes. A dry cell is placed under the coil and all is included in a neat box. The handles form the terminals of the secondary coil. 105. The Currents. It should be noted that the current from the cell does not get into the secondary coil. The coils are thoroughly insulated from each other. The secondary current is an induced one, its voltage depending upon the relative number of turns of wire there are in the two coils. (See Transformers.) The secondary current is an alternating one; that is, it flows in one direction for an insta...