There are many types of piezo buzzers, which can be classified according to current, structure and driving mode. Among them, the most common ones are active piezo buzzers and passive piezo buzzers.
Active piezo buzzers, also known as piezo indicators, have the driving circuit built into the design, operating on a fixed frequency. Active piezo buzzers are easy to operate and make louder sound comparatively, and engineers do not need to design a complex circuit to drive the buzzer.