User's Manual

GE865 Hardware User Guide
1vv0300799 Rev.11 – 13-07-2010
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 60 of 82
11.8 Magnetic Buzzer Concepts
11.8.1 Short Description
A magnetic Buzzer is a sound-generating device with a coil located in the magnetic
circuit consisting of a permanent magnet, an iron core, a high permeable metal disk
and a vibrating diaphragm.
Drawing of the Magnetic Buzzer.
The disk and diaphragm are attracted to the core by the magnetic field. When an
oscillating signal is moved through the coil, it produces a fluctuating magnetic field
which vibrates the diaphragm at a frequency of the drive signal. Thus the sound is
produced relative to the frequency applied.
Diaphragm movement.
11.8.2 Frequency Behaviour
The frequency behaviour represents the effectiveness of the reproduction of the applied
signals. Because performance is related to a square driving waveform (whose