are many different kinds of buzzer to choose, first we need to know a
few parameters, such as voltage, current, drive method, dimension, mounting
type, and the most important thing is how much SPL and frequency we want.
Operating voltage: Normally, the operating voltage for a magnetic
buzzer is from 1.5V to 24V, for a piezo
buzzer is from 3V to 220V. However, in order to get enough SPL, we
suggest giving at least 9V to drive a piezo buzzer.
Driving method: Both magnetic and piezo buzzer have self
drive type to choose. Because of the internal set drive circuit, the self
drive buzzer can emit sound as long as connecting with the direct current.
Due to the different work principle, the magnetic buzzer need to be driven
by 1/2 square waves, and the piezo buzzer need square waves to get better
Consumption current: According to the different
voltage, the consumption current of a magnetic buzzer is from dozens to
hundreds of mill amperes; oppositely, the piezo type saves much more electricity,
only needs a few mill amperes, and consumes three times current when the
buzzer start to work.
Dimension: The dimension of the buzzer affects its SPL
and the frequency, the dimension of the magnetic buzzer is from 7 mm to
25 mm; the piezo buzzer is from 12 mm to 50 mm, or even bigger.
Connecting way: Dip type, Wire type, SMD type, and screwed
type for big piezo buzzer are usually seen.
SPL: Buzzer is usually tested the SPL at the distance
of 10 cm, if distance double, the SPL will decay about 6 dB; oppositely,
the SPL will increase 6 dB when the distance is shortened by one time.
The SPL of the magnetic buzzer can reach to around 85 dB/ 10 cm; the piezo
buzzer can be designed to emit very loud sound, for example, the common
siren, are mostly made of piezo buzzer.
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