Measuring Instruments in Physics - Sensitivity, Range and Linearity

Learn how any measuring instrument in physics has a certain sensitivity, range and linearity depending on its design. NOTE: Mistake at 0:46...

This physics tutorial explores the ideas of sensitivity, range and linearity.

Please note that the video has a mistake at 0:46...
The sensitivity of a sensor is defined as the change in output of the sensor per unit of input signal being measured. Sensitivity may be linear or non linear, depending on the type of sensor.
For example, a thermistor measures temperature and its resistance will change for each 1 degree Celsius change. However, its sensitivity (in V/degree C) is often not linear, so at a higher temperature you may see a smaller change in resistance for each 1C temperature chance.

It's worth mentioning that the RESOLUTION (or PRECISION) of a sensor is the smallest change it can detect in the quantity that it is measuring.
The resolution/precision of a sensor with a digital output is usually the smallest interval of the digital output, for example a hundredth of a volt (0.01V).

The RANGE is the maximum and minimum values that can be measured

A LINEAR RESPONSE means that a graph of the input signal vs output reading would be a straight line (i.e. directly proportional).


So... to summarise:

ACCURACY is how close your measurement is to the "true" value.

PRECISION/RESOLUTION OF AN INSTRUMENT will usually mean the smallest division on the scale or the smallest change in a value that it can measure

PRECISION FOR A SET OF DATA refers to how closely grouped that data is about the mean value. More tightly grouped means higher precision.

SENSITIVITY is usually only used to describe electronic devices, this relates to the response of the device to a unit change in the input. For a measuring instrument it relates to the change in the indicated value that is produced by a unit change in the measured value.
For example, if you have a thermocouple whose output changes by 1mV when the temperature changes by 1 degree C, you could say its sensitivity is 1mV per degC.

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