Hitachi RAS-25WX8 Manuel De Maintenance page 78

6. Buzzer Circuit
• When the buzzer sounds, an approx.
3.9kHz square signal is output from
buzzer output pin
computer. After the amplitude of this
signal has been set to 12Vp-p by a
transistor, it is applied to the buzzer.
The piezoelectric element in the buzzer
oscillates to generate the buzzer's sound.
7. Receive Circuit
12V
• The light receiving unit receives an infrared signal from the wireless remote control. The receiver amplifies
and shapes the signal and outputs it.
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Microcomputer
30
Buzzer output
of the micro
30
Sound wave
Q141 R212
R141
0V
manuals search engine
R219
Fig.6-1 Buzzer Circuit
Metal diaphragm
V
Voo
+
R211
Vout
IRR
-
GND
Fig.7-1
– 77 –
12V
BZ
Q722
0V
Piezoelectric element
V
Fig.6-2 Buzzer Operation
R611
WIRELESS
13
INPUT
Microcomputer
0V