370 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1957 



Fig. 15 — Front and back of typical printed wiring board. 



were treated on an independent basis, thus providing maximum flexibil- 

 ity in application. While the use of transistors made it possible to take 

 advantage of miniaturized components, the major emphasis in design 

 has not been on miniaturization; instead it has been to achieve low manu- 

 facturing costs, simplicity of engineering and installation, and a mini- 

 mum of maintenance effort. The recent trend toward automation in 



