Sensor - The Electronic Nose Artificial Olfaction Technology - page 28

Fig. 2.3 Transducer configuration with the use of sensor

intensity, etc., and the sensor output is conditioned and analyzed to provide the
equivalent measurement of the physical property.

2.2.1 Criteria to Choose a Sensor

There are certain features to be considered while choosing a sensor. They are:

1. Accuracy
2. Environmental condition—usually has limits for temperature/humidity
3. Range—Measurement limit of sensor
4. Calibration—Essential for most of the measuring devices as the readings
changes with time
5. Resolution—Smallest increment detected by the sensor
6. Cost
7. Repeatability—The reading that varies is repeatedly measured under the same
environment

Sensors do not operate by themselves. They are generally part of a larger
system consisting of signal conditioners and various analog or digital signal
processing circuits. The system could be a measurement system, data acquisition
system, or process control system. We will not cover all possible types of sensors
but discuss popular types of sensors such as: Temperature, Flow, Pressure, Level,
displacement, positional, etc.