Rev. 0.2 / 09 /2015
10
AN1111-2
The nominal characteristic of the device (HCT01 sensor together with electronics) can be determined
by measurement at various levels of relative humidity.
Figure 7: Example of nominal characteristic
The deviation from the reference RH after correcting for PCB influences and hysteresis is shown in
Figure 8.
Figure 8: Initial accurate electronics – w/o C_Cal: PCB corrected
0
10
20
30
40
50
60
70
80
90
100
0
10
20
30
40
50
60
70
80
90
100
di
gi
ta
l c
ap
ac
ita
nc
e v
al
ues
[p
F]
relative humidity [% rH]
Example of nominal characteristic @3V3
-5,0
-4,0
-3,0
-2,0
-1,0
0,0
1,0
2,0
3,0
4,0
5,0
0
20
40
60
80
100
de
vi
at
io
n
re
la
tiv
e
hu
mi
di
ty
[% rH
]
relative humidity [% rH]
Initial accurate electronics, 55 units @3V3
w/o C_CAL ; PCB corrected ; w/o hysteresis; nominal
characeristic
