Fig. 7 illustrates transient dynamic current response of the sensor at 390 ◦C, when exposed to 50,000 ppm of CO mixed in dry air. It is clear from the figure that it took 45 s for the current to reach to its maximum value (peak response time). The sensor recovers back to its initial value within 25 s. The same results within ±5% variation in time were observed at other operating temperatures. Furthermore,the overall shift in the current base line to higher values with temperature is observed due to the change in film resistance with operating temperature.