مدار آزیر 100 دسی بل با آی سی 555 - SIREN 100dB Circuit

This is a very loud siren and if two or more piezo's are located in a room, the
burglar does not know where the sound is coming from.

A robber will not
stay anywhere with an ear-piercing sound as he cannot hear if someone is
approaching. It's the best deterrent you can get. The "F" contact on the piezo
is "feedback" and is not needed in this circuit.