"This investigation involves the construction of an analog computer model of the transistor. The computer model is based upon the Linvill diffusion model. The equations for the Linvill diffusion model were programmed on the computer by making certain approximations. Different models, using different approximations, were used for the different regions of operation of the transistor. A composite analog model was constructed by combining the models for the restricted regions, giving a general model good for all regions of transistor operation. This analog diffusion model was modified to account for the effects of junction capacitance and base resistance. The modified analog model was then used to run programs to show the effects of junction capacitance and base resistance on the behavior of the transistor. It was also used to run programs for comparison of the analog model and an actual transistor. Most of these programs were run by the UMR Computer Center on the Pactolus analog simulator program. The comparison of the analog model and the actual transistor was accomplished by comparison of the responses (in terms of collector current) of the analog model and a p-n-p transistor in switching from cutoff to saturation. The analog model gave results which correspond closely with the experimental results over most regions of operation. However, it was found that the effects of junction capacitance cannot be exactly duplicated by the model. Also, the relays used in the analog model to change the approximations when the transistor changes regions of operation, cause serious errors in some cases. For switching circuits (or other circuits where there is a large variation in the magnitude of the variables), the range of the variables causes a severe scaling problem for the analog computer. Extension of the analog model to include such things as base width modulation, variation of the model parameters with current, and the like, is possible but it greatly increases model complexity and accuracy is still limited by the factors mentioned above"--Abstract, page ii-iii.
Dillman, Norman G., 1938-2010
Carson, Ralph S.
Bain, Lee J., 1939-
Electrical and Computer Engineering
M.S. in Electrical Engineering
University of Missouri at Rolla
x, 68 pages
© 1968 Clifford D. Skouby, All rights reserved.
Thesis - Open Access
Analog computer simulation
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Electronic OCLC #
Link to Catalog Record
Skouby, Clifford D., "A simulation of the transistor by computer using the Linvill diffusion model" (1968). Masters Theses. 5214.