Show THE HOME YME RADIO how to make and aselt c cap by ByA copyright A HYATT by jyLL VERRILL A broth XII transformers these are instruments designed to transform or change one kind of electrical current to another such ns as alternating current to a direct current and are very useful and essential devices in radio telephony there are many kinds of trans formers fo foi imers but all are built or rather based upon the same principles which Is that ot of inductance or the formation of a current in a coll coil of wire by the passage of another current through another coll coil near it As in deuced currents are only produced when the magnetic field Is clanging changing the current induced by a transformer can only lie be secured by means of some mechanical ch device or by an alternating current when the alic former la is used the transformer becomes a spark coll or 4 7 L aj r as I 1 m X 9 27 ri a 6 71 an af J aa art frt PAIT f foci rl fray rius induction coll coil see coils and the means by atch which the gilmary nry current li iq alternately nl broken or interrupted Is N the buzzer or contact at the end of the iron core of the coll coil gut but if an current lq 19 run the primary wires of a transformer no interrupter la Is required as the magnetic field changes each time the alie current rises and falls there are two emeral types of transformers in use one known as an open trans doimer foi roer which Is exactly like an ordinary dir tary sparking coll coil and consists of in 1111 iron core covered with two wind lues jigs of alre ire known as the primary und and second a ry 28 A very often such a transformer can he be used an ordinary coll coil alth the alie contact in eaker screwed down answers very ery purpose the other type Is known as the closed core transformer and consists of a number of iron plates or laminations in the form of a hollow square and which are wound on one side for the primary and on the opposite side tor for the sc secondary condar fig 28 B although either one of those these types may be made at home yet it la 19 not advisable to attempt it in the first place several thousand turns of secondary secondary wire are required and it Is a tedious and difficult matter to wind these on evenly and well moreover the number of turns of gilmary and secondary wire must ile he very carefully proportioned and must be worked out on mathematical rua lines in order to secure the proper reactance or tile the tendency to resist the flow of the alternating current finally are not expensive and the cheapest are far more effi efficient clent and are better made tillin anything that you can make your belf |