what is the wheatstone bridge and how is it used in air sampling

The Wheatstone Bridge is a very interesting part of Gas sensors that occupational hygienists use in their field work. Industrial hygienists use these gas meters to find if there are any contaminants in the workplace. Some weigh a few pounds while others only weigh a few ounces. This may not seem like a big deal but it matters when you have to put them on worker and expect them to wear it for their entire shift. What you find more often time then not is these workers will lake them off and put them down someplace else. This gives the occupational hygienists wrong readings and therefore wrong data collected. Or they may still have the gas sensor on them but they will have tucked the hose into their pocket because they don’t like having the hose taped on their body. Because of this it is important that the occupational health hygienist checks up on the workers around an hour after placing it on them. If they don’t do thins they could waste the entire day. Anyway back to the bridge. Basically the circuit is what the device uses to detect the toxic compounds or element in the air. There is a part of the bridge that has a heating compound that reacts with the combustible gases that are being sucked into the contraption. This heats up the heating compound and causes a specific temperature that is correlated with a number or reading. This then tells you how much combustible gas is in that area. There are other sensors that essentially do the same things as the Wheatstone bridge. There are two big ones, one of which is named metal oxide semiconductor, and the second is thermal conductivity. The names are pretty self-explanatory. The metal oxide detects metals that have oxidized in the air while the thermal conductivity, which measures how well the air pumped in conducts heat.