586 BELL SYSTEM TECHNICAL JOURNAL 



is the low-frequency amplification factor: 



Z=Mo| ^^-ZTz^ J. U4) 



Z" = r (^2 + Z3 + Z.)Z„ + (Zi + Zo)Z. 1 _ ^j3^ 



L /ioZo — Zi + Z3 J 



Figure 7 is the form taken by Fig. 12 for moderately high frequencies 

 where transit angle effects are just beginning to become noticeable. 



In general, the formulas for the impedances in the delta network 

 are just as long as in the original network of Fig. 8. The delta may, 

 however, have an advantage in view of its wide use in low-frequency 

 work, and of the fact that the amplification factor for the delta can be 

 expressed without involving the transit angle, and hence does not 

 contain a phase shift. 



