Midea AWCA034ADB

Service Manual_2018-V1.0
30
The characteristic that resistance value reduces as the temperature increases is deemed to have
negative slope or negative temperature coefficient (NTC), and such thermistor is called as NTC thermistor.
The resistance value changes sensitively with temperature and typically changes 7% ~ 3% per degree
centigrade. Sensor used in the refrigerator is NTC thermistor.
There is following computing formula for the sensor:Sampling voltage / reference voltage =
R1 / (RNTC + R1)
AD value / reference AD value = R1 / (RNTC + R1)
The reference voltage is 5V, RNTC is the resistance value of the sensor, R1 is R31\R32\R33 in schematic
diagram that is 5.1K
10.3 Temperature test circuit(None)
10.4 Freezer chamber fan motor circuit (None)
10.5 refrigerating chamber fan motor circuit (None)
10.6 Condensation fan circuit (None)
10.7 Fan motor circuit of the ventilation door(None)
10.8 Resistance value of the sensor (R/T) (None)
Tx(℃)
R（KΩ）
Tx(℃)
R（KΩ）
Tx(℃)
R（KΩ）
Tx(℃)
R（KΩ）
Tx(℃)
R（KΩ）
-30
33.81
-15
14.31
0
6.495
15
3.141
30
1.617
-29
31.85
-14
13.55
1
6.175
16
2.999
31
1.55
-28
30.01
-13
12.83
2
5.873
17
2.865
32
1.486
-27
28.29
-12
12.16
3
5.587
18
2.737
33
1.426
-26
26.68
-11
11.52
4
5.315
19
2.616
34
1.368
-25
25.17
-10
10.92
5
5.06
20
2.501
35
1.312
-24
23.76
-9
10.35
6
4.818
21
2.391
36
1.259
-23
22.43
-8
9.82
7
4.589
22
2.287
37
1.209
-22
21.18
-7
9.316
8
4.372
23
2.188
38
1.161