For dynamic characteristics of any instruments out of the following which qualities are desirable? i. Speed of response ii. Lag iii. Fidelity iv. Dynamic error

For dynamic characteristics of any instruments out of the following which qualities are desirable? i. Speed of response ii. Lag iii. Fidelity iv. Dynamic error Correct Answer i, iii only correct

The performance characteristics of an instrument are mainly divided into two categories: 

i) Dynamic characteristics 

ii) Static characteristics 

Dynamic characteristics: 

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

 i) Speed of response

 ii) Measuring lag

 iii) Fidelity

iv) Dynamic error

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  

(i) Fidelity: It is defined as the degree to which a measuring instrument is capable of faithfully reproducing the changes in input, without any dynamic error.  

(ii) Resolution: It is the smallest quantity being measured which can be detected with certainty by an instrument.

(iii) Threshold: If the instrument input is increased very gradually from zero there will be some minimum value below which no output change can be detected. This minimum value defines the threshold of the instrument. 

(iv) Hysteresis:  Hysteresis is a phenomenon that illustrates the different output effects when loading and unloading.