Sensor Performance Characteristics

Sensor Performance Characteristics

Transfer function

• The functional relationship between stimulus (input) x and sensor output y is called transfer function. 
• The functional relationship between physical input signal and electrical output signal.
• 𝑦 = 𝑓 (𝑥)
• Linear or nonlinear
• One dimensional or multi dimensional
• Single input, single output
• Multiple inputs, single output

Sensitivity

• Sensitivity of a sensor is defined as the change in output for a given change in input, usually a unit change in input.
• Sensitivity represents the slope of the transfer function.
• The ratio between a small change in electrical signal to a small change in physical signal or derivative of the transfer function with respect to physical signal.

Resolution

• Resolution is the minimal change of the input that can produce a detectable increment in the output signal.
• Ex : A temperature sensing system with four digits has a higher resolution than three digits.

Bandwidth

• All sensors have finite response times to an instantaneous change in physical signal.
• Bandwidth: the distance in Hz between the half power points Half-power points: eh=0.707e, ph=0.5p

Accuracy

• The accuracy of the sensor is the maximum difference that will exist between the actual value and the indicated value at the output of the sensor.

Precision

• Precision represents capacity of a sensor to give the same reading when repetitively measuring the same input under the same conditions.

Author : Laahiru Fernando.