TGS2442 Datasheet, PDF (8/25 Pages) List of Unclassifed Manufacturers – Detection of Carbon Monoxide

TECHNICAL INFORMATION FOR TGS2442
3-3 Gas response pattern
The response pattern of the TGS2442 sensor is similar
to that of a constant VH sensor since data acquisition
is carried out once every second during operation.
Figure 9 shows the pattern of the output signal when
the sensor is placed into 70, 150, and 400ppm of CO
and then returned to normal air. The response time
to 90% of the saturated signal level is roughly 3.3
minutes and the recovery of the sensor to 90% of the
base level is within 10 minutes. This data
demonstrates that TGS2442 possesses sufficient
response speed for meeting UL requirements for CO
detectors.
1000
70ppm CO
400ppm
air
150ppm CO
air
CO
air
100
10
0 20 40 60 80 100 120 140 160
Time (min)
Figure 9 - TGS2442 response pattern in 70, 150, and 400ppm CO
3-4 Heater voltage dependency
10
The TGS2442 should be used with a heater voltage
of 4.8 ± 0.2V. Although at the detection point the
sensor’s temperature is close to room temperature,
its gas sensing characteristics are affected by heater
voltage as can be seen in Figure 10. At lower heater
1
voltage, the Rs/Ro decreases and the difference in
sensitivity between CO concentrations narrows. If
heater voltages is higher, sensor resistance increases.
CO 30ppm
CO 100ppm
CO 300ppm
0.1
4.2
4.4
4.6
4.8
5.0
5.2
5.4
Heater voltage (V)
Figure 10 - Heater voltage dependency
(Ro = Rs at 100ppm of CO and VH=4.8V)
Revised 03/00
6