Datasheet

ManualsBrandsFIGARO ManualsSensorsTGS-813 Gas Sensor Type Propane, butane, methane, alcohol, hydrogen (Ø x H) 17 mm x 10 mm

GENERAL CHARACTERISTICS

TGS

#813

is a general purpose

Sensor

which has good sensitivity characteristics

to a wide range of

gases.

TGS ß813 is designed to operate with a

stabilized

heater

supply

and

circuit voltage not exceeding 24V.

. ..The most suitable

application

for the TGS

#813

is the

detection

of methane,

propane and butane which makes it an

excellent

Sensor

for

domestic

gas leak

detectors.

. ..The initial stabilization

time

of the TGS 8813 is very short and the relative

and elapsed characteristics are very good over a long period of Operation.

TGS

#813

has a very low sensitivity to

'noise-gases'

which considerably

reduces

the

Problem

of nuisance alarming.

The TGS 8813 is most practically employed in a circuit design which maintains

circuit voltages at fixed values

under

24V (Ex.

5,6,12,

24V

are suitable)

and with the heater voltage stabilized at 5V.

These

voltage

ratings are very practical when determining your design specifications

because

of the wide range of available components.

This makes the use of the

TGS

#813

an especially econimical way to design low-tost, highly reliable gas

detection circuits.

Because of its especially high sensitivity to methane, propane and butane, the

TGS

#813

very

practical for Town Gas and LPG monitoring.

With the added

features of a

short-initial

stabilization period and highly reliable elapsed

characteristics,

the TGS

#813

represents a new generation of gas Sensors from

Figaro.

Summary of content (20 pages)

PAGE 1
GENERAL CHARACTERISTICS . . . TGS #813 is a general purpose Sensor which has good sensitivity characteristics to a wide range of gases. . . . TGS ß813 is designed to operate with a stabilized 5V heater supply and a circuit voltage not exceeding 24V. . ..The most suitable application for the TGS #813 is the detection of methane, propane and butane which makes it an excellent Sensor for domestic gas leak detectors. . ..
PAGE 2
1. Structure and Configuration of the TGS #813 Resin moulding FIG.l. TGS #813 CONFIGURATION. l(4) 3(6) 26) 5(2) @ 4(l) 601 FIG.2. TGS #813 DIAGRAM OF THE ELECTRIC CIRCUIT. l Remarks: Pins numbered 1 and 3 are connected internally. Pins numbered 4 and 6 are connected internally. Dimensions in millrmeter FIG.3. TGS #813 STRUCTURAL SPECIFICATIONS. Figs.l & 3 show the structure and configuration of the TGS ß813 Sensor.
PAGE 3
TABLE 1 VIBRATION AND SHOCK TEST 1. VIBRATION TEST + Condltlons: 1 OOOcpm Frequency 4mm Total amplitudes Ihr. Duration Direction of Vibration Verticai (3) 2. SHOCK TEST + Condltions: Acceleration Number of lests 100G.
PAGE 4
2. Basic Measuring Circuit Vc : Circuit Voltage Vn : Heater Voltage RL : Load Resistance FIG. 4. BASIC MEASURING CIRCUIT WITH TGS SENSOR. Fig.4 Shows the basic test circuit for use with Sensor type 8813. The Variation in resistance of the TGS sensoris measuredindirectly as a Change in voltage appearing across the load resistor RL. In fresh air the current passing through the Sensor and RL in series is steady, but when a combustible gas such as propane, methaoe etc.
PAGE 5
3. Circuit Configurations Table II lists the safe operating area for type ß813 Sensor. The values of VC, VH and PS cannot be exceeded. Subject to a maximum Sensor dissipation of 15 mW, the values of VC and RL tan be Chosen to meet design requirements. In practice VC tan be 5,6,12 or 24 Volts, and be supplied from a hattery or A.C. Source. When using the basic circuit PS (Sensor power dissipation) becomes maximum when RS = RL. We strongly recommend that the value of PS be kept under 15 mW.
PAGE 6
4. STANDARD TEST CONDITIONS AND SENSOR SPECIFICATIONS Table TH Standard Test Conditions 1. Atmospheric Condition Fresh air with 20°C 2 2°C and R.H. 65% f 5% 2 . Circuit Condition: Basic measuring circuit vc : lov + o.lv, VH : 5.OOV + O.O5V, RL :4.OK - OHM 2 1% 3. Conditioning Time: 7 days or more 4. Test Gas: Methane Gas The Standard conditions under which the TGS 8813 should be tested are illusWe must stress the importante of adhering to these contrated in Table III. ditions for several reasons.
PAGE 7
5. SENSITIVITY CHARACTERISTICS Concentration (ppm) FIG. 5. RATIO OF RESISTANCE (R/Ro) vs. CONCENTRATION FOR $813. l Remarks: Ra: Sensor resistance in air conlaming 1000ppm of Me!hane. Fl: Sensor resistance at different concentrations of gases. Fig.5 Shows the changing resistance values of the type 8813.sensor in relation to various types and concentrations of gases. This graph is fixed at 1000 ppm of methane.
PAGE 8
6. DEPENDENGY ON HEATER VOLTAGE Fig. 6 Shows the effect of VH fluctuation on the TGS #813's sensitivity. This value is based on the R/Ro value for methane at 1000 ppm with an illustrated + 4% Variation of heater voltage. You should note the general principle that if the heater voltage varies both the resistance andconsequentlythe alram Point for the various gases will Change accordingly. Thus, we recommend that your heater voltage be stabilized with a less than + 1% Variation.
PAGE 9
7. TEMPERATURE AND HUMIDITY The sensitivity characteristics of the TGS $813 Sensor are altered by changes in atmospheric temperature and humidity. The detection principle of the TGS is based on Chemical adsorption and desorption of gases on the Sensor surface. Because these reactions are temperature dependent and water vapour tan be considered a gas, the effects of temperature and humidity changes cannot be eliminated from the Sensor.
PAGE 10
1.2 x 1.1 . 1.0 0.9 0.8 Ambienttemperature Fig.8 TGS #813. TEMPERATURE DEPENDENCE IN AIR CONTAINING VARIED L CONCENTRATIONS METHANE. Test condition: Vc 1OV A.C. / VH 5.0V A.C. / RL 4KQ Atmospheric condition: Temperature is changed at a fixed humidity of 0.2g HzO/kg Air or less. Measuring procedure: At respective temperature,wait for Outputs in air to stabilize and measure Outputs in gas. Following each Change of temperature allow 2~3 hours for Sensors to stabilize at the new test conditions.
PAGE 11
2oac-0 x 63’x 40°C;.0% 20) lOO'% (R H. at 20°C) 4OYo 9,z 1.0 09 0.8 I u a9 0 8 2 e 0.7 0.6 0.5 0.4 0.3 Ambient humidity Fig.9 TGS #813 HUMIDITY DEPENDENCE IN AIR CONTAINING VAkIED CONCENTRATIONS METHANE. Test condition: Vc 1OV A.C. / VH 5.0V A.C. / RL 4KR Atmospheric condition: Humidity is changed at a fixed temperature of 40°C. Measuring procedure: At respective humidity conditions, wait for Outputs in air to stabilize and measure Outputs in gas.
PAGE 12
8. TIME FOR INITIAL STABILIZATION A TGS Sensor which has been stored unenergized for a lang period takes some time to resch its normal operating condition following switch on. This "Initial Action" characteristic in fresh air is shown in Fig.10. From the moment of switch on the sensor's conductivity first rises rapidly and then falls towards its final stable value. The time taken to stabilize is a function of the sensor's storage time and atmosphere.
PAGE 13
9. TIME DEPENDENCY CHARACTERISTICS Fig:ll shows a.typical Pattern for a TGS #813 Sensor which has been stored unenergized for a long period of.time. This graph Shows Sensor resistance at a constant gas concentration. When the Sensor is energized after a lang storage period it takes approximately 1-10 days for the Sensor to resch a stable resistance level.
PAGE 14
10. SENSOR LIFE The data in Fig. 12 Shows fluctuations.in sensitivity with time based over Current a 9 year period using some of the TGS Sensors originally produced. since then but retain the TGS Sensors have been considerably improved Same time dependency characteristics as the early q odels. Fig.12 Shows similar data on long term Operation, but is specifically related to TGS #813 Performance.
PAGE 15
012 3 4 5 6 7 9 910. ‘feim Fig.12 LONG TERM OPERATION Sample: TGS #15S Test'condition: Vc 1OOV A.C. / VH l.OV A.C. / RL 4KQ Test gas: Isobutane lOOOppm/air 2 8 ’ i? 3.5 2 1 Years P 3 I Fig.13 LONG TERM OPERATION Sample: TGS #813 (100 pieces) Test condition: Vc 1OV A.C. / VH 5.OV A.C.
PAGE 16
11. PRACTICAL DETECTOR CIRCUIT USING THE #813 SENSOR As was mentioned above the TGS #813 is suitable for use in the detection of a wide range of gases such as naturalgas, L.P.G. and town gas. Wben you design a circuit employing the TGS #813 you must consider both the type and concentration of gas you wish to detect. Because of its sensitivity characteristics, the action of the Sensor will vary according to the type and concentration of gas it is detecting.
PAGE 17
TEMPERATURE AND HUMIDITY COMPENSATION METHOD As was previously mentioned, Sensor resistance (Rs) is dependent upon the ambient temperature and humidity. Accordingly, this phenomenon will result in a fluctuation of the alarming Point. Possible variations in the effects of temperature and humidity changes are illustrated in TableV. This Variation in Sensor Performance, however, is primarily related to the measure of Absolute Humidity in the detecting area.
PAGE 18
PAGE 19
Table V CHANGES IN ALARM POINT RESULTING FROM TEMPERATURE FLUCTUATIONS AT FIXED HUMIDITY Gas Concentration at Alarm(Methane/Air: ppm) Measuring Condition Temperature ("0 Humidity (% RH) Circuit Compensated for Temperature Circuit Not Compensated for Temperature * 20 65 3000 3000 -10 65 2950 5200 65 3100 1800 65 2600 1400 5, 35 c * Original alarm calibration conditions
PAGE 20
..:.]’ 3.0 ..;... 3.1 3.2 3.3 Temperature 3.4 - 3.5 1 -x103 T 3.b (20) 3.