Structure and Dimensions:

1 Sensing Element:

the surface of an alumina ceramic tube

which contains an internal heater.

2 Sensor Base:

Alumina ceramic

3 Flame Arrestor:

100 mesh SUS 316 double gauze

Item

Symbol

Rated

Values

Remarks

Heater

Voltage

VH

5.0±0.2V

AC or DC

Circuit

Voltage

VC

Max. 24V

AC or DC

*PS 15mW

Load

Resistance

RL

Variable

*PS 15mW

Standard Circuit Conditions:

Pin Connection and Basic Measuring Circuit:

The numbers shown around the sensor symbol in the circuit diagram at the

right correspond with the pin numbers shown in the sensor's structure drawing

(above). When the sensor is connected as shown in the basic circuit, output

creases, depending on gas concentration.

Sensor Resistance (Rs) is calculated by

the following formula:

Rs = (

Power dissipation across sensor electrodes

(Ps) is calculated by the following formula:

Ps =

2

2

Standard Test Conditions:

TGS 821 complies with the above electrical characteristics

when the sensor is tested in standard conditions as speci-

fied below:

Test Gas Conditions:

20

°±2°C, 65±5%R.H.

Circuit Conditions:

±0.1V (AC or DC),

±0.05V (AC or DC),

Ω±1%

Preheating period before testing: More than 7 days

Electrical Characteristics:

Rs

Basic Measuring Circuit:

REV: 9/99

α

Item

Symbol

Condition

Specification

Sensor

Resistance

Hydrogen at 100ppm/Air

1k ~ 10k

Change Ratio of

Sensor Resistance

Log[Rs(H2 100ppm)/Rs(H2 1000ppm)]

Log (1000ppm / 100ppm)

0.6~1.20

Heater

Resistance

Room temperature

38.0 ± 3.0

Heater Power

Consumption

VH=5.0V

660 ± 55 mW

FIGARO USA, INC.

3703 West Lake Ave. Suite 203

Glenview, Illinois 60025

Phone:

(847)-832-1701

Fax:

(847)-832-1705

email: figarousa@figarosensor.com

For information on warranty, please refer to Standard Terms and

Conditions of Sale of Figaro USA Inc.

um : mm

19.5

± 0.5

1.0

± 0.05

13.5

+ 0.3

- 0.2

9.5

± 0.3

6

3

4

2

5

1