PDF《FIGARO》

Applications: Features: TGS

832 - for the detection of Chlorofluorocarbons (CFC'

s) The figure below represents typical sensitivity char-acteristics, 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 at 100ppm of R-134a 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 100ppm of R-134a at various temperatures/humidities Ro = Sensor resistance at 100ppm of R-134a at 20°C and 65% R.H. The sensing element of Figaro gas sensors is a tin dioxide (SnO2) semiconductor which has low conductivity in clean air. In the presence of a detectable gas, the sensor'

s conductivity increases depending on the gas concentration in the air. A simple electrical circuit can convert the change in conductivity to an output signal which corresponds to the gas concentration. The TGS

832 has high sensitivity to R-134a, the most promising alternative to R-12, commonlyusedinairconditioningsystemsandrefrigerators. R-12andR-22arealso detectable by TGS 832. With its good long term stability, TGS

832 is an excellent, low-cost sensor for CFC detection. * Refrigerant leak detector * High sensitivity to R-134a * Quick response to R-134a * Improved selectivity * Long term stability * Uses simple electrical circuit * Ceramic base resistant to severe environment Temperature/Humidity Dependency: Sensitivity Characteristics: FIGARO PRODUCT INFORMATION 0.01 0.1

1 10

100 1000 Rs/Ro

30 Concentration (ppm) .05 0.5

5 50

300 500

3000 Air R-12 R-134a Ethanol R-22 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2.0 -10

0 10

20 30

40 50

60 Rs/Ro Ambient Temperature (°C) 40% R.H. 65% R.H. 100% R.H. 1.2 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 across the Load Resistor (VRL) increases as the sensor'

s resistance (Rs) decreases, depending on gas concentration. Sensor Resistance (Rs) is calculated by the following formula: Rs = ( -1) x RL VC VRL Power dissipation across sensor electrodes (Ps) is calculated by the following formula: Ps =

2 VC x Rs

2 (Rs + RL) Standard Test Conditions: TGS

832 complies with the above electrical characteristics when the sensor is tested in standard conditions as specified below: Test Gas Conditions: 20°±2°C, 65±5%R.H. Circuit Conditions: VC = 10.0±0.1V (AC or DC), VH = 5.0±0.05V (AC or DC), RL = 10.0k?±1% Preheating period before testing: More than

7 days Electrical Characteristics: FIGARO USA, INC.

3703 West Lake Ave. Suite

203 Wilmette, Illinois

60091 Phone: (847)-832-1701 Fax: (847)-832-1705 email: figarousa@figarosensor.com Basic Measuring Circuit: REV: 8/92 Structure and Dimensions:

1 Sensing Element: SnO2 is sintered to form a thick film on 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 um : mm 19.5 ± 0.5 1.0 ± 0.05 13.5 + 0.3 - 0.2 9.5 ± 0.3 11.0 ± 0.2 23.0 ± 1.0 3.0 ± 0.2 6.5 ± 0.2

6 3

4 2

5 1

4 5 ?

4 5 ? m e t I l o b m y S s e u l a V d e t a R s k r a m e R e g a t l o V r e t a e H VH