Transistor applications

• Main Author: Moore, William Cullen
• Language: en_US
• Published: Boston University 2013
• Online Access: https://hdl.handle.net/2144/5855

Thesis (M.A.)--Boston University === The Transistor is a new device employing a semi-conductor base material in conjunction with multiple point contacts to perform many of the functions of vacuum tubes. Although the unit is still in an embryonic stage, its many advantages offer incentive for research. A convenient subject cross-file for analysis of reference data is described. The history of amplifying crystals is outlined for the period beginning 1923 to June, 1948. An analogy is draw between the commercial history of previous inventions end the present status of the Transistor. The history and publicity accorded the Transistor are presented, and analyzed in terms of its potential acceptance as a commercial electronic component. Recently reported developments and public demonstrations are discussed. Sketches and micro-photographs show the details of contacts and germanium wafers as currently produced. Size is compared with standard components. Possibilities for mass production are considered. A brief survey of the theory of conduction in semi-conductors is given as a basis for the theory of Transistor action. An analogy to space charge control is offered. Transistor action is described and typical results presented. Analysis of the action by the use of total derivatives shows that the reflex trans-conductance term describes an effect which cause the voltage across the input terminals to reverse and throw the unit into a regenerative state of operation. The methods of dimensional analysis are employed to investigate the possible combinations of parameters which can occur. It is found that free charge cannot be one of these parameters. The trans-conductance is seen to be a function of the collector impedance. Experiments on the construction of Transistors from 1N34 germanium diode parts are described. Microphotographs show the stages of assembly. Test equipment and procedures are described. Typical circuits and results are give in diagrams and graphs. It is found that units suitable for low performance applications can be assembled satisfactorily on an experimental basis. Characteristics. of twenty-three commercial units are tabulated and are found to disperse widely on a scatter diagram. Performance of units in various circuits is analyzed. A simple R-C oscillator circuit, based on the presence of like phase at input and output, is investigated and found to have interesting and useful properties. The reversal of emitter voltage is experimentally verified. The potential applications of Transistors are evaluated in terms of known and anticipated characteristics. Twenty advantages and fifteen disadvantages are briefly summarized in decreasing order of importance. Circuit functions are divided into five generic groups. Within each group the specific type of circuit is discussed in terms of Transistor characteristics. Any predominantly advantageous specific applications are mentioned. A bibliography of fifty-nine references on Transistors is appended.