Gas detectors

[rolf]

How do they work?

[hotdog]

Not very technical, but... A gas detector has a sensor that can detect tiny changes in thermal conductivity. When the detector is switched on, it takes its bearings from the air immediately around it, then a suction pump constantly draws in air which is run over the sensor. When a change in the sample is detected, an audible alarm usually sounds and the reading is shown on a screen. Better than using canaries.