If you are unsure about how to use a semicolon, have a look at Gary Olson’s Punctuation Made Simple, which points to two major scenarios: (1) the semi-colon as a connector of two sentences, (2) the semi-colon as a “supercomma.” Purdue University’s Writing Lab addresses the first scenario in a useful comparison of the semicolon and comma in compound sentences. Besides serving as a connector of two independent clauses (otherwise known as sentences), the semicolon helps connect such sentences using a conjunctive adverb such as however or nevertheless. The examples on these two websites are good, so I won’t provide any of my own. Once you think you understand, have a look at the somewhat more detailed semicolon chart offered by the Writing Center at the University of Wisconsin.

Related post: Commas