Several classifications of sensors in a variety of applications

People use the five sense organs to perceive information from the outside world. The sensors send the obtained information into the brain for thinking and judgment, and then the brain commands the "female senses" to feel the external information in a very narrow range (only information that is harmless to the human body), and there are many others that cannot or It is difficult to feel that if the electricity being measured is electricity, it can be directly connected to various intelligent instruments (computers and robots) and perform signal processing. The limbs complete a certain movement. Apparently, the sensor can replace the human five sense organs to complete the function of perceiving information from the outside world, and become a device that transmits feelings (responses).

Measured, such as ultraviolet light, infrared light, electromagnetic field, odorless and odorless gas, ultra-high temperature, highly toxic substances, and various weak signals, etc., and these sensors can sense. Because electrical signals have high precision, high sensitivity, a wide range of measurement and control, easy to transmit, amplify, and feedback, and have many advantages such as continuous measurability, remote measurement, and storage, people hope that the sensor can also amplify and transmit the sensed signal , Storage and display output. Therefore, in a broader sense, the sensor can be summarized as a device that can sense external information (force, heat, sound, light, magnetism, gas, humidity, etc.), and convert it into easy-to-process electrical signals according to certain rules. .

If the measured quantity is non-electricity, such as physical quantity (mechanical quantity, humidity, flow, level, optical quantity and temperature), chemical quantity (composition, pH and reaction speed), biomass (blood pressure, human body reaction), etc., it must pass the corresponding The sensor converts them into electricity, which is then sent to the computer for processing. That is to say, the device that can convert the measured physical quantity or chemical quantity into an electrical output that has a definite opposite relationship is called a sensor (a sensor is also called a transducer, transducer, transmitter, transmitter, or detector, etc. ).