Hitachi RAM-36NP2A, Service Manual, Page: 61 / 87

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1. Receiver Circuit
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The light receiver unit receives the infrared signal from the wireless remote control. The receiver ampli fi es
and shapes the signal and outputs it.
2. Buzzer Circuit
Fig. 2-1 Buzzer Circuit
Fig. 2-2 Buzzer Operation
●
When the buzzer sounds, an approx.
3.9kHz square signal is output from buzzer
output pin of the microcomputer. 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.
DESCRIPTION OF MAIN CIRCUIT OPERATION
MODEL RAI-25RPA, RAI-35RPA, RAI-50RPA
Fig. 1-1
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