Specifications
72 
Figure 30 Output Signal in mV vs. Absolute Humidity in g/M
3
 for Thermal 
Conductivity sensors (Reprinting Permission Requested from Questex 
Media Group LLC) 
Another  name  for  the  Polymer  sensor  is  a  Capacitive  Humidity  sensor. These 
sensors  calculate  the  change in  the  electrical  impedance  using  an  ammonium 
salt  substrate.  The  resistance  of  a  humidity  sensor  is  directly  proportional 
according to its relative humidity. 
Figure 31 shows the linear correlation between capacitance and relative humidity 
for  Capacitive  Humidity  sensors.  This  graph  was  taken  with  a  reference 
measurement at 25 degrees Celsius. 
Figure 31 Capacitance of the capacitors in (pF) vs. Absolute Humidity for 
Thermal Conductivity sensors in (%) (Reprinting Permission Requested 
from Questex Media Group LLC) 
In  choosing  the  best  humidity  sensor  some  of  the  important  concerns  or 
questions that  people come across are how  accurate or precise the sensor is, 










