How Circuits Work

This paper presents a theory of corn monsense understanding of the behavior of electronic circuits. It is based on the intuitive qualitative reasoning electrical engineers use when they analyze circuits. This intuitive reasoning provides a great deal of important information about the operation of the circuit, which although qualitative in nature, describes important quantitative aspects of circuit functioning (feedback paths. stability, impedance and gain estimates. etc.). One aspect of the theory. causal analysis. describes how the behavior of the individual components can be combined to explain the behavior of composite systems. Another aspect of the theory. teleological analysis, describes how the notion that the system has a purpose can be used to structure and aid this causal analysis. The theory is implemented in a computer program. EOL’AL. which, given a circuit topology, can construct by qualitative causal analysis a description of the mechanism by which the circuit operates. This mechanism is then parsed by a grammar for circuit functions.