The word "sensor" is often thrown around in the context of technological capabilities, but what are these components exactly? Sensors are essential instruments that help to facilitate automation in devices that we use every day. With the seemingly endless amount of sensor applications and classifications, it can be difficult for customers to choose the product that is best suited for their specific needs. In this blog, we will discuss the operating principles of sensors and highlight the nuances involved in choosing a particular device.
A sensor is a device that can produce an effect in response to a stimulus. This stimulus may be physical, chemical, or electrical, while the sensor's output commonly exists as information sent to a computer processor. One of the simplest forms of a sensor is a thermistor
, which employs a diode made from ceramic materials that slightly deform when exposed to changes in temperature. The majority of thermistors are designed to have a negative temperature coefficient, causing their resistance to maintain an inverse relationship with temperature. Thus, as the sensor is exposed to heat, its resistance drops in a predictable manner which may be calculated and sent as information to a paired device.
Infrared sensors make use of the invisible portion of the electromagnetic spectrum, particularly that which produces wavelengths of 700nm to 1mm. This light, which is invisible to humans, forms the basis for active and passive sensors used in gas analysis, radiation strength, and contactless temperature management. Many infrared sensors use semiconductor
materials capable of succumbing to the photoelectric effect, in which the material absorbs electromagnetic radiation from infrared light.
Proximity sensors quickly detect nearby objects without having to make physical contact, making them valuable tools for proximity-induced touch screens, ground warning systems, and automotive parking technology. Since proximity sensors lack components that must come into contact with other objects, they generally have long operational lifespans compared to other sensors. While some variance exists between individual products, most proximity sensors project a nonvisible wave of electromagnetic radiation and detect changes in the return signal. As the sensor draws closer to an object, the magnitude of deformations in the electromagnetic signal will significantly increase.
Pressure sensors are valuable components used to determine the pressure of gas or liquid. Although pressure may be defined by different physical quanlities depending on the application, these sensors measure the force over the unit area that the fluid exerts. For example, pressure sensors are used to determine height based on the linear inverse relationship between pressure and altitude in aviation. Another use for pressure sensors is in flow measurement. Using the principles of the venturi effect, sensors calculate the pressure difference between two points in an enclosed tube, which is directly proportional to the flow rate.
Capacitive position sensors measure a target object's change in capacitance value to infer information about its location. Like proximity sensors, capacitive position sensors can produce highly accurate information without the need for physical contact. The capacitance may be calculated by forming a ratio of the material dielectric constant times the area, divided by the distance between two objects. As such, a decrease in distance would cause a predictable and easily measurable change in capacitance if the object's dielectric constant and area is known.
When purchasing sensors for any application
, it is critical to procure them through a trusted source. At ASAP Logistic Solutions, we provide customers with cost savings and rapid lead times on an unparalleled inventory of over 2 billion ready-to-purchase items. As an AS9120B, ISO 9001:2015, and FAA AC 00-56B accredited enterprise, we implement several quality assurance strategies to ensure we distribute the highest caliber products possible. We are also the only independent distributor to uphold a strict NO CHINA Sourcing policy, ensuring every order is fully traceable or comes directly from a reputable manufacturer. To get started on the purchasing process today, simply browse our offerings and submit an RFQ for any item you are interested in.