Sensors fall into two main categories: passive and active. Passive sensors do not require a power source, while active sensors do. Active sensors emit radiation, such as infrared or ultrasonic waves, and detect reflected energy.
Passive sensors do not send their own radiation but instead detect the radiation emitted by a target object. Both types of sensors are useful in a variety of applications, including security surveillance, traffic monitoring, and consumer electronics.
An accelerometer is one of the most common types of sensor. It measures the change in a force and transmits the information back to electronics or computers. It is used in touch-sensitive lamps, elevator buttons, and more.
If you want to know more about the four classifications of sensors, continue reading this article.
What Are the Four Classifications of Sensors?
Before we go any further, let’s discuss the different types of sensors. There are two main types: passive and active. These categories can be further subdivided into two further classifications.
- Active and Passive Sensors
When it comes to measuring physical quantities, active and passive sensors differ considerably. Active sensors emit or receive energy from the environment, such as electromagnetic fields, and they also record the reflected energy from objects. In contrast, passive sensors do not generate any energy; they derive this energy from the phenomena they are measuring. A camera is a good example of a passive sensor. Its light sensitivity reflects the amount of reflected light. The difference between active and passive sensors is primarily a question of technology. An active sensor can be anything that requires energy, such as a remote sensing satellite.
- Contact and Non-Contact Sensors
Since non-contact sensors have a longer service life and can withstand harsh conditions, the demand for them has increased. These sensors are used for a variety of applications in various industries. Depending on the type, different non-contact sensor technologies have different principles and applications. Inductive sensors, for instance, operate on the transformer principle. They measure linear position without the need for calibration. They are also ideal for applications in the automotive industry. A non-contact sensor, on the other hand, is capable of detecting its own temperature, even if no heat transfer takes place.
- Absolute and Relative Sensors
Absolute and relative sensors measure pressures differently. Relative pressure sensors measure the pressure inside tires, and absolute pressure sensors measure pressures outside the tire. The differences in performance are based on the application and the measurement range. This article will discuss the fundamental differences between absolute and relative sensors and how each works. The difference between absolute and relative sensors lies in their reference points. Absolute sensors measure pressure in relation to a vacuum, while relative ones measure pressure in relation to the atmosphere.
- Analog and Digital Sensors
Analog and digital sensors measure two different things. Analog quantities are continuous in nature, such as pressure, displacement, strain, or temperature. For example, thermometers measure liquid temperature by responding to changes in its temperature. Pressure sensors, on the other hand, measure force per unit area. Typically, pressure is measured in psi, and their response to a change is based on the amount of force applied to the object. These sensors also function as transducers to measure other parameters. Analog and digital sensors each have their advantages and disadvantages. Analog sensors are more accurate and efficient than digital ones, but they are often less expensive and have fewer limitations. Digital sensors also have higher transmission rates and negligible distortion.