The operational tag often appears on questions about op amps. In many cases questions would be tagged with both operational and amplifier instead of the single, correct operational-amplifier (at least, until I recently fixed the tags on such questions). It seems as if users often type "operational amplifier" in the tags input box and get both tags instead of the single correct one.
Of the questions which are still tagged operational all but one really have to do with op amps and should be tagged with operational-amplifier. There is one question which seems to use operational in the sense of "will this be operational?" but I don't see much use for this tag in that sense, especially in light of the fact that it is often used for questions involving op amps.
Would it make sense to make operational a synonym of operational-amplifier in the hope that users will be more likely to tag questions correctly? We might still get questions tagged with both operational-amplifier and amplifier but at least the latter is generally applicable to questions about op amps whereas operational doesn't really make any sense on its own.