INDUCTANCES AND RESISTANCES 



which, if k is nearly unity, simplifies to 



Kout 1 



'in 



^(1 - k^)o,L, r + RX^ il-k^+ ' + ^^ ^'^''' 



Rl + Rs 



(oL, 



n^ 



Rl + Rs 



w 



r 



-o — \A-nj5r^ I 



w\rv^ 



Figure 4.36 



-WW — "THnnnnr^ 



Rf,*r V. .-,.p 







-o- 

 I 



Figure 4.37 



This is plotted as a function of frequency in Graph 21 for various values of k 

 and for 3 degrees of loading 



Light load— ^i_^ ^ io(i?^ + r) —full lines 



n" 



Matched load — — ^ ^ — - = i?j, + r — chain-dotted lines 



Heavy load- 



n" 



Rs + Rl 



«2 



= 0-l(Rj, + r) — dashed Hnes 



Evidently a transformer is a band-pass device having 6 dB/octave attenua- 

 tion slopes at each end of the pass-band. The lower turn-over frequency 

 occurs at 



a>i = 



ir + RJ^^^) 





69 



