The static characteristics of a sensor refer to the correlation between the output and input of the sensor for the static input signal. Since the input quantity and the output quantity are independent of time, the relationship between them, i.e., the static characteristics of the sensor, can be described by an algebraic equation without time variables, or by drawing a characteristic curve with the input quantity as the abscissa and the corresponding output quantity as the ordinate. The main parameters that characterize the static characteristics of the sensor are: linearity, sensitivity, hysteresis, repeatability, drift, etc.

(1) Linearity: refers to the degree to which the actual relationship curve between the output and input of the sensor deviates from the fitting straight line. Defined as the ratio of the maximum deviation between the actual characteristic curve and the fitted line over the full scale range to the full-scale output.

(2) Sensitivity: Sensitivity is an important indicator of the static characteristics of a sensor. It is defined as the ratio of the increment of the output to the corresponding increment of the input that caused the increment. S is used to indicate sensitivity.

(3) Hysteresis: The phenomenon that the input and output characteristic curves of the sensor do not coincide during the change of input quantity from small to large (positive stroke) and input quantity from large to small (reverse stroke). For input signals of the same size, the output signals of the forward and reverse strokes of the sensor are not equal, and this difference is called the hysteresis difference.

(4) Repeatability: Repeatability refers to the degree to which the characteristic curves obtained by the sensor are inconsistent when the input quantity changes the full scale several times in the same direction.

(5) Drift: The drift of the sensor refers to the change of the output of the sensor with time under the condition that the input amount remains unchanged, and the secondary phenomenon is called drift. There are two reasons for drift: one is the structural parameters of the sensor itself; The second is the surrounding environment (such as temperature, humidity, etc.).