Compact size Low sensitivity to alcohol vapor For residential CO detectors - Figaro Engineering - #1

TGS 2442 utilizes a multilayer sensor structure. A glass layer for thermal insulation is printed between a ruthenium oxide (RuCte) heater and an alumina substrate. A pair of Au electrodes for the heater are formed on a thermal insulator. The gas sensing layer, which is formed of tin dioxide (SnCte), is printed on an electrical insulation layer which covers the heater. A pair of Au electrodes for measuring sensor resistance are formed on the electrical insulator. Activated charcoal is filled between the internal cover and the outer cover for the purpose of reducing the influence of noise gases.

TGS 2442 displays good selectivity to carbon monoxide, making it ideal for CO monitors. In the presence of CO, the sensor's conductivity increases depending on the gas concentration in the air. A simple pulsed electrical circuit operating on a one second circuit voltage cycle can convert the change in conductivity to an output signal which corresponds to gas concentration.

The figure below represents typical sensitivity characteristics, all data having been gathered at standard test conditions (see reverse side of this sheet). The Y-axis is indicated as sensor resistance ratio (Rs/Ro) which is defined as follows:

Rs = Sensor resistance of displayed gases at various concentrations

Ro = Sensor resistance in 100ppm CO

Sensitivity Characteristics:

The figure below represents typical temperature and humidity dependency characteristics. Again, the Y-axis is indicated as sensor resistance ratio (Rs/Ro), defined as follows:

Rs = Sensor resistance at 30ppm, 100ppm and 300ppm

of CO at various temperatures and 50%R.H. Ro = Sensor resistance at 300ppm of CO at 25°C and 50% R.H.

Temperature/Humidity Dependency:

100

1000

10

100

10

1

1

0.1

0.1

0.01

-20 -10 0 10 20 30 Temperature (°C)

40 50

60

1

10 100 1000

Gas Concentration (ppm)

10000

IMPORTANT NOTE: operating conditions in which figaro sensors are used will vary with each customer's specific applications. figaro strongly rec­ommends consulting our technical staff before deploying figaro sensors in your application and, in particular, when customer's target gases are not listed herein. figaro cannot assume any responsibility for any use of its sensors in a product or application for which sensor has not been specifically tested by figaro.