516 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



Junction Transistor. M. Sparks^. Set. Am., 187, pp. 29-32, July, 1952. 



It is one of two forms of the remarkable device that amphfies electricity by the 

 flow of electrons in a crystal. An account of its underlying principles and present 

 state of development. 



Telephone Answering Services. L. R. Stang^ Telephony, 143, pp. 53- 

 55, 123-124, Oct. 25, 1952. 



Traffic Engineering Design of Dial Telephone Exchanges. J. A. 

 Stewart^ Telephony, 143, pp. 13-16, 41-42, Oct. 18, 1952. 



Low-Drain Transistor Audio Oscillator. D. E. Thomas^. I.R.E., Proc, 

 40, pp. 1385-1395, Nov., 1952. 



A nine-element transistor audio oscillator is described. This oscillator operates 

 with relatively low drain from a single 6-volt battery. The oscillator gives re- 

 liable performance with an output uniform to approximately dbl db with sub- 

 stantially all type 1768 point-contact transistors and without any circuit element 

 adjustment required for variation in transistor parameters from unit to unit or 

 with transistor ambient temperature. 



Trandstor Amplifier — Cutoff Frequency. D. E. Thomas^ I.R.E., Proc, 

 40, pp. 1481-1483, Nov., 1952. 



The effect of positive feedback through the internal base resistance of a transis- 

 tor on circuit cutoff frequency is considered. 



Transistor Reversible Binary Counter. R. L. Trent^ I.R.E., Proc, 40, 

 pp. 1562-1572, Nov., 1952. 



The feasibility of performing a fairly complex switching function using a few 

 elementary transistor circuits is illustrated and experimentally verified. The 

 specific function discussed is reversible vinary counting. The mechanism used to 

 achieve reversibility and the circuitry within each building block is described. 

 Operating margins and suggestions for design improvements for systems applica- 

 tion are given. 



Effect of Electrode Spacing on the Equivalent Base Resistance of Point- 

 Contact Transistors. L. B. Valdes^. I.R.E., Proc, 40, pp. 1429-1434, 

 Nov., 1952. 



A theoretical expression for the equivalent base resistance rb of point-contact 

 transistors is derived here. This expression is shown to check experimental 

 values reasonably well if the severity of some assumptions made for purposes of 

 analysis is considered. Electrode spacing, germanium-slice thickness, and re- 

 sistivity of the semiconductor are shown to be the properties that affect rj, 

 primarily. 



* Bell Telephone Laboratories. 



• Illinois Bell Telephone Company. 



