Sensors

Sensors are sophisticated devices that are frequently used to detect and respond to electrical or optical signals. A Sensor converts the physical parameter (for example: temperature, pressure, humidity, speed, etc.) into a signal which can be measured electrically. Let’s explain the example of temperature. The mercury in the glass thermometer expands and contracts the liquid to convert the measured temperature which can be read by a viewer on the calibrated glass tube.

Criteria to choose a Sensor

There are certain features which have to be considered when we choose a sensor. They are as given below:

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

Classification of Sensors

The sensors are classified into the following criteria:

1. Primary Input quantity (Measurand)
2. Transduction principles (Using physical and chemical effects)
3. Material and Technology
4. Property
5. Application