Calculation of Circuits by the Algebra of Logic
In 1937 a research assistant at Massachusetts Institute of Technology, Claude E. Shannon, was studying for his degree of master of science. He was enrolled in the Department of Electrical Engineering. He was interested in automatic switching circuits and wondered why an algebra should not apply to them. He wrote his thesis on the answer to this question and showed that:
(1) There is an algebra that applies to switching circuits.
(2) It is the algebra of logic.
A paper, based on his thesis, was published in 1938 in the Transactions of the American Institute of Electrical Engineers with the title “A Symbolic Analysis of Relay and Switching Circuits.”
For a simple example of what Shannon found out, suppose that we have two switches, 1, 2, in series (see Fig. 1). When do we get current flowing from the source to the sink? There are 4 possible cases and results (see Table 9).