Classification of Sensors and Actuators

Flashcards related to sensors and actuators, covering definitions, characteristics, and types.

Sensor

A device that responds to a physical stimulus and transmits a resulting impulse.

Transducer

A device that converts power of one form into power of another form.

Actuator

A mechanism for moving or controlling something indirectly instead of by hand.

Static Characteristics

Characteristics that describe how a sensor behaves when the input is constant.

Dynamic Characteristics

Characteristics that tell how a sensor behaves when the input changes with time.

Accuracy

The capacity of a measuring instrument to give results close to the true value of the measured quantity.

Precision

The capacity of a measuring instrument to give the same reading when repetitively measuring the same quantity under the same prescribed conditions.

Sensitivity

The output to the unit change of input; the ratio between an incremental change in output to the corresponding change in input.

Linearity

Indicates whether the output characteristics of the sensor follow a linear equation.

Hysteresis

Deviation of the sensor’s output at a specified point of input signal when it is approached from opposite directions.

Selectivity

Defines how selective the sensor is for the target parameter or material.

Repeatability

Variation of a measurement when other conditions, such as time or observer, are the same.

Resolution

The smallest increment of the stimulus that can be detected by a sensor.

Dead band

The range in which a sensor shows insensitivity to a stimulus.

Stability

How robust the sensor or system is; can be mechanically, electrically, or chemically stable.

Span

The arithmetic difference between the highest and lowest values of the stimulus that can be sensed within acceptable errors.

Zero-order Sensor

A sensor with no delays that only changes the amplitude of the input signal.

First-order Sensor

A sensor with one element that stores energy and one that dissipates it.

Second-order Sensor

A sensor related by a second-order differential equation, often characterized by damping coefficients.

Response Time

Time to pass between 10% to 90% of the steady state value of the response.

Settling Time

Time taken to settle down to within ±1% of the steady state value.