FIGARO PRODUCT INFORMATION TGS 2611 - for the detection of Methane Features: Applications: * Low power consumption * High sensitivity to methane * Long life and low cost * Uses simple electrical circuit * Domestic gas alarms * Portable gas detectors * Gas leak detector for gas appliances The sensing element is comprised of a metal oxide semiconductor layer formed on an alumina substrate of a sensing chip together with an integrated heater. 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 2611 has high sensitivity and selectivity to methane gas. Due to its low sensitivity to alcohol vapors (a typical interference gas in the domestic environment), the sensor is ideal for domestic gas alarms. Due to miniaturization of the sensing chip, TGS 2611 requires a heater current of only 56mA and the device is housed in a standard TO-5 package. The figure below represents typical sensitivity characteristics, 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 in displayed gases at various concentrations Ro = Sensor resistance in 5000ppm of methane 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 in 5000ppm of methane at various temperatures/humidities Ro = Sensor resistance in 5000ppm of methane at 20°C and 65% R.H. Sensitivity Characteristics: Temperature/Humidity Dependency: 100 10 10 35%RH 50%RH 65%RH 95%RH Rs/Ro Rs/Ro Air 1 Ethanol Hydrogen Iso-butane 1 Methane Gas: 5000ppm methane 0.1 0.1 100 1000 10000 Gas concentration (ppm) 100000 -20 -10 0 10 20 30 40 50 Ambient temperature (˚C) 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. Basic Measuring Circuit: The sensor requires two voltage inputs: heater voltage (VH) and circuit voltage (VC). The heater voltage (VH) is applied to the integrated heater in order to maintain the sensing element at a specific temperature which is optimal for sensing. Circuit voltage (VC) is applied to allow measurement of voltage (VRL) across a load resistor (RL) which is connected in series with the sensor. A common power supply circuit can be used for both VC and VH to fulfill the sensor's electrical requirements. The value of the load resistor (RL) should be chosen to optimize the alarm threshold value, keeping power dissipation (PS) of the semiconductor below a limit of 15mW. Power dissipation (PS) will be highest when the value of Rs is equal to RL on exposure to gas. Specifications: Structure and Dimensions: Top view Model number TGS 2611 Sensing element type D1 Standard package TO-5 metal can Target gases Methane, Natural Gas Typical detection range 500 ~ 10,000 ppm Standard circuit conditions Electrical characteristics under standard test conditions VH Circuit voltage VC 5.0±0.2V DC Ps ≤ 15mW Load resistance RL Variable Ps ≤ 15mW Heater resistance RH 59Ω at room temp. (typical) Heater current IH 56 ± 5mA Heater power consumption PH 280±25mW Sensor resistance Rs 0.68~6.8 kΩ in 5000ppm methane Sensitivity (change ratio of Rs) Test gas conditions Standard test conditions 5.0±0.2V DC/AC Heater Voltage 0.60 ± 0.06 Methane in air at 20±2˚C, 65±5%RH Conditioning period before test PS = (VC - VRL)2 RS 7 days Sensor resistance (Rs) is calculated with a measured value of VRL by using the following formula: RS = VC - VRL VRL x RL For information on warranty, please refer to Standard Terms and Conditions of Sale of Figaro USA Inc. REV: 9/99 Bottom view VC = 5.0±0.01V DC VH = 5.0±0.05V DC Circuit conditions The value of power dissipation (PS) can be calculated by utilizing the following formula: Rs (9000ppm) Rs (3000ppm) Side view FIGARO USA, INC. 3703 West Lake Ave. Suite 203 Glenview, Illinois 60025 Phone: (847)-832-1701 Fax: (847)-832-1705 email: [email protected]