Simple Electronic Buzzer

This very simple circuit just uses a couple of resistors, a capacitor and the easily available 555 timer IC.
The 555 is setup as an astable multivibrator operating at a frequency of about 1kHz that produces a shrill noise when switched on. The frequency can be changed by varying the 10K resistorhttp://www.electronic-circuits-diagrams.com/alarmsimages/5.gif