Product Name: formaldehyde gas detection sensor MQ138 ( with analog and TTL level signal output )
Product Features
One size : 32mm X22mm X30mm L * W * H
Second， the main chip : LM393， formaldehyde sensing probe
Third， the working voltage : DC 5V
Four characteristics:
1， with the signal output LED indicates ;
2 ， dual signal output ( analog output ， and TTL level output ) ;
3， TTL output valid signal is low ; ( lights lit when the output is low， which can be accessed microcontroller IO port )
4 ， analog output increases with the concentration ， the higher the concentration the higher the voltage ;
5 of aldehydes ， alcohols ， ketones ， aromatic compounds having a high sensitivity ;
6， with a long life and reliable stability ;
7 ， rapid response and recovery characteristics ;
8 ， with mounting holes for easy fixed installation ;
9 ， the probe can plug design for easy testing .
V. Application :
For home volatiles environment detection means suitable for the detection of aldehydes， alcohols ， ketones ， aromatic compounds ， and the gas sensitive element concentration ranges :
Benzene 1 to 100ppm
Toluene 10 to 100ppm
Methanol 5 to 100ppm
Alcohol 30 to 300ppm
Acetone 10 to 300ppm
Formaldehyde 1 to 10ppm
Reference routines ， circuit diagrams and instructions probe