To use a fishing analogy, the chip is the bait and the reactive molecules in the sample are the fish. Different baits are used to attract different fish, and when a fish takes the bait (when reactive DNA segments bind to the probes) it pulls on the line, alerting the angler.
若以釣魚來比喻，晶片就是魚餌，要加入的反應分子則是魚，不同的魚餌釣不同的魚，當魚兒上鉤（即探針與反應 DNA 片段結合），就會扯動釣線告知魚訊。