Classification of sensors (or transducers) based on physical stimuli

 

Classification of Sensors

The scheme of classifying sensors can range from very simple to very complex. The stimulus that is being sensed is an important factor in this classification.

Some of the stimuli are

  • Acoustic: Wave, spectrum, and wave velocity.
  • Electric: Current, charge, potential, electric field, permittivity, and conductivity.
  • Magnetic: Magnetic field, magnetic flux, and permeability.
  • Thermal: Temperature, specific heat and thermal conductivity.
  • Mechanical: Position, acceleration, force, pressure, stress, strain, mass, density, momentum, torque, shape, orientation, roughness, stiffness, compliance, crystallinity, and structural.
  • Optical: Wave, wave velocity, refractive index, reflectivity, absorption, and emissivity.

The sensors’ conversion phenomenon is also an important factor in the classification of sensors. Some of the conversion phenomena are 

  • magnetoelectric, 
  • thermoelectric 
  • photoelectric.

Comments

Post a Comment

Popular posts from this blog

Washing Machine: An example of mechatronics system

Image
The washing machine is an example of a  sequential control system.  A system operating with sequential control is one where a number of preset operations are performed in sequence.  The control may be implemented as  event-based,  where the next action cannot be performed until the previous action is completed.  Another mode of sequential control is termed  "time-based",  where the operations are sequenced with respect to time. Example: An example of a time-based sequential control system is shown in the following Figure 1. The pump (fill valve) is switched ON for a particular time to fill enough water into the tank to fill it to approximately the correct level. Following this, the pump is switched OFF.   Figure 1: Time-based sequential control Among these two modes,  event-based control  is intrinsically  more reliable  than time-based control.  An example of an event-based sequential control system is a washing machine. In this system, a number of operations or events h
Read more

Proximity sensors

Image
Proximity sensors Proximity sensors are pilot devices used to detect the presence of an object without making any physical contact and are widely used in industrial automation for the detection of objects at a position. Proximity sensors are a non-contact type of solid-state electronic devices and are normally of eddy current type or inductive, capacitive or photoelectric proximity sensor. Inductive proximity sensor An inductive proximity sensor is a non-contact proximity sensor that can detect ferrous objects that contain iron, ideally mild steel thicker than one millimeter. Construction: An inductive proximity sensor is a non-contact proximity sensor that detects ferrous objects that contain iron, ideally mild steel thicker than one millimeter.  An inductive proximity sensor consists of four major components: a ferrite core with coils , an oscillator , a detector or signal conditioner , and an output amplifier all packed in a compact housing.   The oscillator creates a symmetrical
Read more

Piezoelectric Pressure Sensor

Image
Piezoelectric Pressure Sensor A piezoelectric sensor is a device that uses the piezoelectric effect to measure changes in pressure, force, strain or temperature by converting them to an electrical charge.  The word piezo is derived from the Greek word piezein which means “Press” or “Stress”. The piezoelectric effect is observed in various materials available in different forms such as crystalline, ceramics, lead-free piezoceramics, semiconductors, and polymers. The  Lead zirconate titanate and quartz crystal are the common types of piezoelectric materials used in piezoelectric pressure sensors.  The piezoelectric material can be referred to as a bidirectional transducer as it generates an internal voltage resulting from an applied pressure or mechanical force due to piezoelectric the effect, contrarily,  it can also generate internal pressure or mechanical strain when an electric field is applied due to the inverse piezoelectric effect.  Construction: The piezoelectric pressure senso
Read more