The SP-11 is a tin di-oxide semiconductor gas sensor which has a high sensitivity to  methane, propane, butane

and other hydrocarbons with reduced sensitivity to alcohol. The SP-11 is suitable forgeneral hydrocarbon gas detection.

Structure

Gas sensitive semiconductor material is formed on the alumina substrate on which the gold electrodes are printed. A thick film heater of ruthenium oxide is printed on the reverse of the substrate and placed in the plastic

Operating conditions

Fig 2 shows the standard operating circuit for this model. The change of the sensor resistance (RS) is obtained as the change of the output voltage across the fixed or variable resistor (RL). In order to obtain the best performance and specified characteristics, the values of the heater voltage (VH) circuit  voltage (VC) and load resistance (RL)

must be within the range of values given in the standard operating conditions shown in the Specification table on the next page. Sensitivity characteristics Fig 3 shows the sensitivitycharacteristics curves of the SP-11 (typical data). Sensitivity characteristics of the FIS gas sensors are expressed by the resistance and gas concentration.

The sensor resistance decreases with an increase of gas concentration based on a logarithmic function.

The sensitivity characteristics of the SP-11 is specified by the following parameters.

• Sensor resistance level: at methane 3000 ppm

• Sensor resistance change ratio: between methane 1000 and 3000 ppm

See the specification table on thenext page for further details. The SP-11 is a tin di-oxide semiconductor gas sensor which has a high sensitivity to methane, propane, butane and other hydrocarbons with reduced sensitivity to alcohol. The SP-11 is suitable for general hydrocarbon gas detection.

Structure

Gas sensitive semiconductor material is formed on the alumina substrate on which the gold electrodes are printed. A thick film heater of ruthenium oxide is printed on the reverse of the substrate and placed in the plastic housing (Fig 1). Operating conditions

Fig 2 shows the standard operating

circuit for this model. The change of the sensor resistance (RS) is output voltage across the fixed or variable resistor (RL). In order to obtain the best performance and specified characteristics, the values of the heater voltage (VH) circuit voltage (VC) and load resistance (RL) must be within the range of values given in the standard operating conditions shown in the Specification table on the next page. Sensitivity characteristics Fig 3 shows the sensitivity characteristics curves of the SP-11 (typical data). Sensitivity characteristics of the FIS gas sensors are expressed by the  relationship between the sensor resistance and gas concentration. The sensor resistance decreases with an increase of gas concentration based on a logarithmic function. The sensitivity characteristics of the SP-11 is specified by the following parameters. • Sensor resistance level: at methane 3000 ppm

•Sensor resistance change ratio: between methane 1000 and 3000 ppm See the specification table on the next page for further details.