First, we develop a type of logic grammar called Extended DCSG. This logic grammar not only defines the syntactic structures of free-word-order languages but also defines relationships between syntactic structures and their meanings. Next, we view electronic circuits as a free-word-order language, and write an Extended DCSG grammar for this language. Relationships between circuit structures and their functions are defined as grammar rules. The Extended DCSG grammar rules are converted into a logic program that parses electronic circuits and derives their functions and behaviors as meanings. These functions and behaviors are finally translated into natural language for explanation.