Datasheet

ManualsBrandsFIGARO ManualsSensorsTGS-3870 gas sensor (Ø x H) 9.2 mm x 13 mm

Revised 08/12

TECHNICAL INFORMATION FOR TGS3870

Technical Information for Combination Methane and

Carbon Monoxide Sensors

The Figaro TGS3870 sensor is a

new small bead-type metal oxide

semiconductor. The sensor’s

miniature size and cyclic heater

operation enable its single

sensing element to be highly

selective to both carbon monoxide

and methane and to show low

power consumption.

Specifications Page

Features..................................................................................................2

Applications...............................................................................................2

Structure...........................................................................................2

 Specications.............................................................................................3

 Dimensions...................................................................................................3

Standard Test Conditions........................................................................4

Basic Measuring Circuit...................................................................................4

Basic Sensitivity Characteristics

Sensitivity to Various Gases............................................................4

Temperature Dependency..................................................................5

Humidity Dependency...................................................................6

Gas Response......................................................................................6

Initial Action...................................................................................7

Long-Term Stability...............................................................................7

Reliability

False Alarm Test................................................................................................8

 InuenceofSiliconeGas...............................................................................9

Corrosion Test...............................................................................................10

Variable Ambient Temperature Test............................................................11

Temperature Cycle Test.................................................................................12

Cautions...................................................................................................................12

See also Technical Brochure “Technical Information on Usage of TGS Gas Sensors

for Explosive/Toxic Gas Alarming”.

an ISO9001 company

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.

TGS3870 is a UL recognized component in accordance with the

requirements of UL2075. Please note that component recognition

testing has conrmed long term stability in 60ppm of methane and 15ppm

of carbon monoxide; other characteristics shown in this brochure have not

been conrmed by UL as part of component recognition.

Summary of content (13 pages)

PAGE 1
an ISO9001 company TECHNICAL INFORMATION FOR TGS3870 Technical Information for Combination Methane and Carbon Monoxide Sensors The Figaro TGS3870 sensor is a new small bead-type metal oxide semiconductor. The sensor ’s miniature size and cyclic heater operation enable its single sensing element to be highly selective to both carbon monoxide and methane and to show low power consumption. Specifications Page Features............................................................................................
PAGE 2
TECHNICAL INFORMATION FOR TGS3870 1. Specifications 1-1 Features Stainless steel gauze * Miniature size and low power consumption * High sensitivity and selectivity to both methane and carbon monoxide (CO) * Low sensitivity to alcohol vapor * Long life and low cost Charcoal filter Lead wire Heater coil 1-2 Applications * Combination methane and CO detectors Sensing Element 1-3 Structure Base Figure 1 shows the structure of TGS3870.
PAGE 3
TECHNICAL INFORMATION FOR TGS3870 1-4 Specifications 1-5 Dimensions Model number TGS3870 Sensing element type Micro-bead Standard package Plastic base and metal can Target gases Methane and Carrbon Monoxide Typical detection range Methane 500 ~ 12,500ppm Carbon monoxide 50~1,000ppm VH Circuit voltage VC RL variable (>0.75kΩ) Heater resistance RH 3Ω±0.3Ω at room temp. Sensor resistance PH RS 120mW VHH = 0.9V DC 11mW VHL = 0.2V DC 38mW average ø8.1 ± 0.2 0.35kΩ~3.
PAGE 4
TECHNICAL INFORMATION FOR TGS3870 1-6 Standard test conditions Standard test conditions for all data shown in this brochure were as follows: Preheating of sensor: 5 days VH (H/L): 0.9V/0.2V (see timing chart, Fig. 2) VC: 5.0V pulse (see timing chart, Fig. 2) VH 1.7 Basic measuring circuit (-) Circuit voltage (Vc) should be applied only at the moment when the signal is taken from the sensor (please refer to Fig. 2): *for methane--5.0V for 5msec. following VH of 0.9V for 4.985 sec. *for CO--5.
PAGE 5
TECHNICAL INFORMATION FOR TGS3870 2-2 Temperature dependency 10 Methane 1000ppm Methane 3000ppm Methane 9000ppm 65% RH Rs/Ro good. In comparison to CO, sensitivity to hydrogen is very low as indicated by the extremely high concentrations of hydrogen required to approximate very low CO levels. Cross-sensitivity to methane is very low according to its high resistance values. 1 Rs/Ro Figures 6a and 6b show the temperature dependency of TGS3870.
PAGE 6
TECHNICAL INFORMATION FOR TGS3870 10 Figures 7a and 7b show the humidity dependency of TGS3870. The Y-axis shows the ratio of sensor resistance for gas concentrations under various atmospheric conditions (Rs) to the sensor resistance at 20˚C and 65%RH (Ro) for 3000ppm of methane (Fig. 7a) and for 100ppm of CO (Fig. 7b). Methane 1000ppm Methane 3000ppm Methane 9000ppm Rs/Ro 2-3 Humidity dependency 1 Rs/Ro 20˚C 0.
PAGE 7
TECHNICAL INFORMATION FOR TGS3870 100 2-5 Initial action circuit be incorporated into the detector’s design (refer to Technical Advisory Technical Information on Usage of TGS Sensors for Toxic and Explosive Gas Leak Detectors). This is especially recommended for intermittent operation devices such as portable gas detectors. 10 Rs(kΩ) VH=0.9 (CH4 sensing) Rs (kΩ) 1 0.1 0 10 20 30 40 Time (min.) 50 60 70 60 70 Figure 9a - Initial action - methane 1000 VH=0.
PAGE 8
TECHNICAL INFORMATION FOR TGS3870 3. Reliability 10 Methane 1000ppm Methane 3000ppm Methane 9000ppm 3-1 False alarming test Rs/Ro test To demonstrate the sensor ’s behavior under continuous low level exposure to CO, samples were tested according to the procedure detailed in UL2034, Sec. 41.1(c)-Stability Test. Test samples were exposed to 30ppm of CO continuously for 30 days under standard circuit conditions.
PAGE 9
TECHNICAL INFORMATION FOR TGS3870 3-2 Influence of silicone gas 1 hour in 10ppm HMDS As this data shows, TGS3870 possesses durability to HMDS exposure. 1 hour after HMDS exposure 1 Rs/Ro Sensor resistance was measured prior to HMDS exposure (Ro), after which energized sensors were placed into an environment of 20˚C and 65%RH. In this environment, sensors were exposed to 10ppm HMDS for a period of 1 hour.
PAGE 10
TECHNICAL INFORMATION FOR TGS3870 3-3 Corrosion test Methane 1000ppm Methane 3000ppm Methane 9000ppm Rs/Ro To demonstrate the durability of TGS3870 against corrosion, samples were subjected to test conditions called for by UL2034, Sec. 57-Corrosion Test. Over a three week period, a mixture of H2S 100ppb, Cl2 20ppb, and NO2 200ppb was supplied to the sensor at a rate sufficient to achieve an air exchange of 5 times per hour.
PAGE 11
TECHNICAL INFORMATION FOR TGS3870 3-4 Variable ambient temperature test test 1 Rs/Ro 3 hours after test 0.1 0 No significant effects can be seen on the CO sensing characteristics of the sensor during and after this test, while methane sensing characteristics were unaffected by this test.
PAGE 12
TECHNICAL INFORMATION FOR TGS3870 3-5 Temperature cycle test Methane 1000ppm Methane 3000ppm Methane 9000ppm test Rs/Ro In accordance with UL2034, Sec. 41.1(e)-Stability Test, test samples were exposed to ten cycles (<1 hour and > 15 minutes) of temperature from 0˚C and 100%RH to 49˚C and 40%RH. As the two test measurements taken 8 hours after the conclusion of the test period demonstrate, sensors subjected to this test show negligible influence on CO and methane sensing by temperature extremes.
PAGE 13
TECHNICAL INFORMATION FOR TGS3870 content atmosphere. 8) Polarization The sensor has polarity. An incorrect Vc connection may cause significant detrioration of long term stability. Connect Vc according to specifications. 9) Soldering Sensors should be manually soldered--wave soldering is not recommended. The high heat generated during wave soldering may deform the resin parts and damage the sensor (e.g. the pressure-fitted sensor cap may separate from the base).