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7.4
Sensor circuit
This circuit detects the temperature by dividing voltage
with resistance and sensor and bringing the voltage value
into CPU, using the characteristics of the sensor that re-
sistance varies with different temperatures.
TE is for defrosting, while TL is for low ambient cooling
operation. TD is to protect the compressor from over-
heating.
7.2
12V power source circuit
Outdoor PC board produces full-wave rectification by
diode bridge (DB50) followed by the provision of tran-
sistor (Q50) produces DC power source at 12V.
7.3
5V watchdog timer circuit
Basically, the same description as the indoor PC board
applies, provided, however, that the reset circuit is not added
to the outdoor side.
Watchdog
timer output
Reset input
To CPU
AC 240V
TD
TE
TL
C10
C11
0.022µ
0.022µ
0.022µ
R37
750K
C09
TF
TF
