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PCRT21ASX Datasheet - Page 8

Download or read online AVX Corporation PCRT21ASX Piezoelectric Acoustic Generators pdf datasheet.



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Piezoelectric Acoustic Generators
Oscillation Type Circuits
3-Terminal Buzzer Type
330k
20k
BZ
A Piezo Transducer with a feedback tab makes the circuit
oscillate without inductors and capacitors. The number of
components is reduced and it is possible to generate from a
sine wave to a trapezoidal wave.
V
Current
cc
155.V
8.2mA
125.V
6.4mA
595.V
4.6mA
565.V
3.0mA
54.5V
2.0mA
535.V
1.1mA
R
1
R
2
Q
1
BZ
In order to increase the sound pressure level, a coil can
be added to the circuit.
NOTE: Wherever possible, the piezo devices should be
capacitive coupled to avoid permanent DC bias and possible
long term damage.
IC Type
V
cc
1k
Q
1
It is easy to build this circuit by using CMOS inverters,
such as MC14049, and MC14069. The oscillation frequency
is in proportion to 1 / R
L
INPUT
R
3
Frequency
2.55kHz
It is easy to do on-off oscillation by using a CMOS
2.55kHz
NAND gate such as MC14011. When the input terminal is
2.55kHz
high, the transducer works. When the input terminal is low, it
2.55kHz
stops.
2.55kHz
2.55kHz
This is an example of a circuit that will generate various
sounds using one MC14069. The frequency determined by
R
C
oscillates 1kHz to 5kHz and 2 times the V
2,
1
to the transducer as V
V
cc
L
R
, C
determines the on and off intervals. It is variable
5
2
in the range of 0.1 to 3 seconds. By changing the switch
position, different sounds are generated.
Position 1:
Position 2:
Position 3:
NOTE: Please investigate in detail to confirm that you will
not be in violation of the patents of others when using the
above circuit examples in volume production.
C
BZ
R
R
1
2
C .
2
C
BZ
R
R
1
2
is applied
cc
.
pp
BZ
1.5k
R
3
R
6
R
R
1
2
220k
C
1
1
10k
30-50k
0.0067 F
V
2
= 9
CC
SW
3
R
7
220k
R
R
C
4
5
= 1 F
2
10k
30-50k
continuous sound
2 different frequencies
interrupted sound
7

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