Oxygen Sensor

The life of the sensor is 2 years, and it can directly measure oxygen in the concentration range of 0-25%. The pins on the bottom of the sensor can be directly connected to a PCB board. This sensor is suitable for portable or fixed safety devices.

Output model

The operation of the oxygen sensor is simple, which is achieved by connecting a low resistance resistor to generate a voltage signal. The maximum voltage signal must not exceed 100mV.

In most cases, a 100Ω resistor is sufficient. In general, the higher the resistance value, the longer the response time of the sensor. It is important to choose a suitable range of resistors to eliminate changes and long-term drift between the sensors due to differences in output current and temperature.

Linear relationship

The signal generated in this oxygen series is slightly non-linear (refer to Figure 2), following the following formula:

Note: If the sensor is calibrated in dry air, the value is 20.9% (S = 20.9, C = 0.209). This results in a K value of 89.14.

In the figure, the percentage concentration of oxygen in both curves is in the range of 0-20.9%, which reflects the relationship between the signal output during the calibration in the air and the oxygen concentration. The maximum deviation occurs when the oxygen concentration is 10%, and the output value is 0.5% lower than the standard value. In most cases, this deviation is negligible, but if necessary, digital technology can be used to compensate.

The output signal depends on the oxygen diffusion rate, which depends on the molecular weight of the carrier gas (Graham's law). The dry air contains 20.95% oxygen, and the remaining nitrogen with a molecular weight of 28, so when the carrier gas used is a gas with a molecular weight greater than that of nitrogen, the output signal will be greatly affected.