Q141
12V
IRR
VDD
Fig.2-1
Fig.3-1 Buzzer circuit
2. Receiver Circuit
IRR (light receiving unit) receives the infrared signal from the wireless remote controller. The receiver
amplifie and shapes the signal and outputs it.
3. Buzzer Circuit
When the buzzer sounds, an approx 3.9kHz
square signal is output from buzzer output pin 30
of the microcomputer. After the amplitude of this
signal has been set to 12Vp-p by IC711, it is
applied to the buzzer. The piezoelectric element
in the buzzer oscillates to generate the buzzer’s
sound.
GND
V
OUT
C211
R212
0V
0V
R211
0V
ZD141
R141
R611
C611
0V
RECEIVER I/P
Microcomputer
13
BZ1
R721
12V
IC711
Microcomputer
Buzzer output
16
1
30
BZ
Sound wave
Metal diaphragm
V
Pizoelectric element
V
Fig. 3-2 Buzzer Operation
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