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Show TRANSFORMERS ' These are Instruments Instru-ments designed to transform or change one kind of electrical current to another such : s alternating current to a direct current, and - are very useful and es- sentlnl devices in radio ' telephony. There are J many kinds of trnns-ii trnns-ii I formers, but all are I Irallt, or rather based, i upon the same princl-1 princl-1 pies, which Is that of " Inductance, or the formation for-mation of a current in 1 coil of wire by the ; passage of another eur-! eur-! rent through another CH nenr It. As in- , duced currents are only ;i produced when the - magnetic field is chang-J chang-J lnS. the current In-ES In-ES duced by a transformer J Mi' only he secured by l "tans of some me-,i me-,i I'hanlcul device or by " ""wnntlng current, i! "hen the former Is !i'osod the transformer ."''I'Wies a spark-coil or VP IMA Ay - ri' -1 1 Autumn rmnsFMum "Wictlim-coil (see coIls) and 6 iiis by which the primary current t j a,ler"ately broken or interrupted ' le h"!er or contact at the end ' ll'e lrn core of the coll. But if 5 alternating current is run through t u'f Drlm'"7 wires of a transformer no , n'7ri,'Pter 'S relulre('. ns the mag-' mag-' rent chnnses each time the cur-il cur-il Sen riSM n"d fulls- Tbere are two 1 Mii"' tJ1S ot transformers in use. for, m " ns ""Pen-circuit transit trans-it Oln!'"' Whk'h ls exm,ty lihe n or-' or-' an i SpnrkInK cil and consists of I 'ro" Cl,re covered with two wind-sj. wind-sj. of wre known as the nrlnin-y ' hVeC0'Uhlry' I,,,g' 2S' A' Verv often. !,,,, s,K'h a transformer can be dint R? '',innr.v spark-coil with the "' e liC,"brcakpr screwed down answers V hmJ PlrPose. The other type Is torn "S tllC "''losed-core trans-1 trans-1 ln.n'1 cons'sts of a number of. t a h or ll,n,lnntlons in the form found sluare and which are lndn on one side for the primary uT the PPosite side for the Flg' 28' B- Although either 'cnne les? tj'Pes mn.v he made at krnpt iV 18 ftot advisable to at-thous, at-thous, In 'the flrst P,nce' several rMui-.j tur.ns of secondary wire nre rai, n and 11 Is a tedious and diffi-tnd diffi-tnd r t0 wlnd these on evenly ' '"Da of iIoreover, the number of . Prtmary and secondary wire ' Very carefully proportioned A ' all. worked out uc nathe- matical lines in order to secure tha proper reactance or the tendency to resist the flow Of the alternating current. cur-rent. Finally, transformers are not expenshe and the cheapest are far more efficient and are better made than anything that you can make yourself. |