CT-161-CD Fujitsu Semiconductor America Inc, CT-161-CD Datasheet - Page 62

• Manufacturer Part Number: CT-161-CD
• Description: KIT 16LX FOR MB90F387
• Manufacturer: Fujitsu Semiconductor America Inc
• Series: F²MC-16LXr
• Type: MCUr

Specifications of CT-161-CD

• Contents: Board, Cable, CD
• For Use With/related Products: MB90F387S
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 865-1103

4.2
A piezoelectric buzzer uses a piezoelectric device as described above. To produce a sound
from the piezoelectric buzzer, you should apply a changing voltage, e.g., AC or pulse voltage,
to the buzzer. Here, let's sound a piezoelectric buzzer by using a pulse wave (pulse voltage)
output from the microcomputer.
4.1.3
When an AC voltage is applied across a piezoelectric crystal, the crystal contracts or
expands alternately each time the direction of current is reversed as shown in Figure 4.3.
The cycle of contraction and expansion changes when the frequency of AC voltage is
varied. This characteristic can be used to vibrate the crystal at various frequencies. If
the vibrational energy of the crystal is large, the crystal can generate an aerial vibration,
which makes a sound. Piezoelectric buzzers use this principle.
Microcomputer and piezoelectric buzzer
Principle of piezoelectric device
Contraction
Figure 4.3 Principle of piezoelectric device
Figure 4.4 Buzzer using a piezoelectric device
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Vibration
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Expansion
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Pulse input
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