Product Introduction
Combustible Gas (Methane) Sensor SB-12A Description:
SB-12A is a tin dioxide semiconductor gas sensor. It has excellent performance for methane detection, high sensitivity, and low power consumption (120mW). It responds quickly, has strong anti-poisoning capability, is insensitive to interfering gases, and is highly reliable in gas detection system applications.
Combustible Gas (Methane) Sensor SB-12A Parameters:
Structure
The gas sensing semiconductor element is bead-shaped with embedded heater coil and electrode wires. The sensing element is mounted in a metal housing with a double-layer stainless steel mesh (100 mesh) in the gas flow path. The mesh has explosion-proof properties. (Fig1)
Operating Conditions
Fig2 shows the standard operating circuit for this model. The change in sensor resistance (RS) can be obtained through the change in output voltage across a fixed or variable resistor (RL). To achieve optimal performance and specified characteristics, the values of heater voltage (VH), circuit voltage (Vc), and load resistance (RL) must be within the ranges specified in the standard operating conditions, as shown in the specification table on the next page.
Sensitivity Characteristics
Fig 3 shows the sensitivity curve (typical data) of SB-12A. The sensitivity characteristics of the gas sensor are expressed by the relationship between sensor resistance and gas concentration. The increase in gas concentration is logarithmically related to the decrease in sensor resistance. The sensitivity characteristics of SB-12A are specified by the following parameters:
--Sensor resistance: in air containing 3000 ppm methane
--Sensor resistance change rate: in air containing 1000 ppm to 3000 ppm methane (slope)
--Sensor resistance change rate: in air containing 3000 ppm methane and 1000 ppm alcohol
Specific Parameters
A. Standard Operating Conditions
| Symbol |
Parameter |
Specification |
Condition |
| VH |
Heater Voltage |
0.90V ± 0.05V |
AC or DC or Pulse |
| VC |
Circuit Voltage |
<5.0V |
DC: Pin 2 (+) Pin 1 (-) |
| RL |
Load Resistance |
Variable (>200Ω) |
PS<10mW |
| RH |
Heater Resistance |
2.8Ω ± 0.2Ω |
Room temperature |
| IH |
Heater Current |
132mA |
IH = VH / RH (typical) |
| PH |
Heater Power Consumption |
120mW |
PH = VH2 / RH (typical) |
B. Environmental Conditions
| Symbol |
Parameter |
Specification |
Condition |
| Tao |
Operating Temperature |
-10~50°C |
Recommended range |
| Tas |
Storage Temperature |
-30~100°C |
|
| RH |
Relative Humidity |
<95%RH |
|
| （O2） |
Oxygen Concentration |
21% ± 1% (standard conditions) |
PhaseFor lower values: >18% |
| Sensitivity parameters are affected by changes in oxygen concentration. |
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C. Sensitivity Parameters
| Model |
SB-12A-00 |
||
| Symbol |
Parameter |
Specification |
Condition |
| RS |
Sensor Resistance |
0.2kΩ~1kΩ |
In air with 3000 ppm methane |
| β |
Sensitivity Slope |
0.45~0.65 |
RS in air with 3000 ppm methane / RS in air with 1000 ppm methane |
| Alcohol Selectivity |
≥ 5.0 |
Rs (in air with 1000 ppm alcohol) / Rs (in air with 3000 ppm methane) |
|
| CH4 Sensitivity |
≥ 9.0 |
Rs (in air) / Rs (in air with 3000 ppm methane) |
|
| Standard test conditions: Temperature: 20 °C ± 2 °C, VC: 5.0 V ± 5% |
|||
| Low Temperature Dependence |
1.2 ± 0.2 |
Rs (in air with 3000 ppm methane at -10°C) / Rs (in air with 3000 ppm methane at 20°C, 65% RH) |
|
| High Temperature Dependence |
0.85 ± 0.15 |
Rs (in air with 3000 ppm methane at 50°C, 60% RH) / Rs (in air with 3000 ppm methane at 20°C, 65% RH) |
|
D. Mechanical Structure Parameters
| Item |
Condition |
Specification |
| Vibration |
Frequency: 5~500Hz |
Should meet satisfactory specifications in sensitivity parameters |
| Shock |
Height: 60cm |
E. Component Materials
| No. |
Part |
Material |
| 1 |
Sensing Element |
SnO2 |
| 2 |
Heater Coil / Wire |
Pt |
| 3 |
Stainless Steel Mesh |
SUS316 |
| 4 |
Carbon Filter Membrane |
Activated Carbon |
| 5 |
Housing |
Nylon 6 (UL94V-0) |
| 6 |
Explosion-proof Mesh |
SUS316 (100 mesh, double layer) |
| 7 |
Metal Outer Box |
Nickel-plated Brass |
| 8 |
Plastic Substrate |
Polybutylene Terephthalate (PBT) |
Volume
