Some Same Sky piezo buzzers include a feedback line. Driving circuits for buzzers with feedback tend to be simpler than circuits for those without. Feedback is accomplished by dividing the piezo element into two electrically isolated pieces. When the main piezo element is actuated it squeezes the feedback portion, creating a voltage on the feedback line. A simple way to use feedback is to have the feedback line connected to the base of a transistor. As the piezo element oscillates the feedback signal will oscillate and the transistor will alternately block or allow current to flow.