This is a circuit I use. When the NPN is turned on the inductor is energized, turn off the transistor and a large counter inductive voltage spike is generated.
As stated in earlier posts its best to drive the piezos at the resonance frequency. Your picture maybe different
Your question about the IC control. The transistor acts as a switch, controlled by the IC. More important it protects the IC as a buffer with it's
higher current handling ability
Bookmarks