|MQ135 Datasheet PDF : 2 Pages |
components. The enveloped MQ-135 have 6 pin ,4 of them are used to fetch signals, and other 2 are used for
providing heating current.
Electric parameter measurement circuit is shown as Fig.2
E. Sensitivity characteristic curve
Fig.2 sensitivity characteristics of the MQ-135
Fig.3 is shows the typical
sensitivity characteristics of
the MQ-135 for several gases.
in their: Temp: 20
O2 concentration 21%
Ro: sensor resistance at 100ppm of
¼ ±× ½
± Íû ª
NH3 in the clean air.
Rs:sensor resistance at various
concentrations of gases.
Fig.4 is shows the typical dependence of
the MQ-135 on temperature and humidity.
85%RH Ro: sensor resistance at 100ppm of NH3 in air
at 33%RH and 20 degree.
Rs: sensor resistance at 100ppm of NH3
at different temperatures and humidities.
- 20 - 10
Resistance value of MQ-135 is difference to various kinds and various concentration gases. So,When using
this components, sensitivity adjustment is very necessary. we recommend that you calibrate the detector for
100ppm NH3 or 50ppm Alcohol concentration in air and use value of Load resistancethat( RL) about 20 KΩ(10KΩ
to 47 KΩ).
When accurately measuring, the proper alarm point for the gas detector should be determined after
considering the temperature and humidity influence.
|Direct download click here|
|Share Link :|