The characteristics of measurement instruments that are helpful to know the performance of instrument and help in measuring any quantity or parameter are known as Performance Characteristics.

Performance characteristics of instruments can be classified into the following two types.

• Static Characteristics
• Dynamic Characteristics

Static characteristics: 

The set of criteria defined for the instruments, which are used to measure the quantities which are slowly varying with time or mostly constant, i.e., do not vary with time, is called ‘static characteristics’. 

The various static characteristics are: 

i) Accuracy  

ii) Precision  

iii) Sensitivity  

iv) Linearity  

v) Reproducibility  

vi) Repeatability  

viii) Threshold  

ix) Drift  

x) Stability  

xi) Tolerance  

xii) Range or span 

All the static performance characteristics of measuring instruments are obtained by Calibration.

Calibration: It is the process of configuring an instrument to provide a result for a sample within an acceptable range. Eliminating or minimizing factors that cause inaccurate measurements is a fundamental aspect of instrumentation design.

Dynamic characteristics: 

The set of criteria defined for the instruments, which are changing rapidly with time, is called ‘dynamic characteristics’. The various dynamic characteristics are:

 i) Speed of response

 ii) Measuring lag

 iii) Fidelity

iv) Dynamic error