Sirén - Piezo screamer

Powerful 6V to 12V piezo alarm. Uses 556, auto-transformer and two piezo alarm elements. Circuit will deliver over 110dB at 1 meter. Uses sweep circuit so there is no need to trim the circuit to match the cavity resonant frequency. We supply a plastic box with two piezo elements (35mm diameter) already mounted in their own resonant cavity. This is part of a commercial alarm unit but it uses our (better!) drive circuit.