Teledyne OT-2 operating instructions Characteristic Input/Output Curve for a Micro-Fuel Cell

2 Operational Theory Model OT-2 System

2.2.5 Calibration Characteristics

Given that the total pressure of the sample gas on the surface of the Micro-Fuel Cell input is constant, a convenient characteris- tic of the cell is that the current produced in an external circuit is directly proportional to the rate at which oxygen molecules reach the cathode, and this rate is directly proportional to the concen- tration of oxygen in the gaseous mixture. In other words it has a linear characteristic curve, as shown in Figure 2-3. Measuring circuits do not have to compensate for nonlinearities.

In addition, since the sensor output is approximately zero in the absence of oxygen, the characteristic curve has close to an absolute zero (within ± 1 ppm oxygen or better, depending on the sensor type and model). In practical application, zeroing may still be used to compensate for the combined zero offsets of the cell and the electronics.

Figure 2-3. Characteristic Input/Output Curve for a Micro-Fuel Cell

2-6 Teledyne Analytical Instruments