This is a unified piezoelectric sounder which has a
piezoelectric diaphragm of 3 terminals connected to a
self drive circuit, and it easily generates sound with
only a DC power supply (DC3.0-20V). Using suitably 
designed resonant system, this type can be used where 
large sound volumes are needed.

Applications
1. Gas alarms, burglar alarms
2. Air conditioners, microwave ovens and various types 
    of microcomputer controlled home-electronic 
    appliances
3. Toys, games, and other simple electronic devices 
    such as teaching aids