Let's start by distinguishing them conceptually. A sensor is a detection device that senses the information being measured and transforms that information into an electrical signal or other required form of output according to a certain rule, to meet the requirements of information transmission, processing, storage, display, recording, and control. A transmitter is a converter that can convert non-standard electrical signals into standard electrical signals according to commands. In short, a transmitter is based on a sensor, converting the information transmitted by the sensor into a signal with a certain rule according to commands. Examples include the commonly heard 485-type temperature and humidity transmitter, analog temperature and humidity transmitter, and GPRS temperature and humidity transmitter. Different sensors measure different parameters, and their working principles and operating conditions vary, resulting in a wide variety of sensor types and specifications. Below, we introduce a centralized classification method for sensors:
Based on the type of object being measured, such as non-electrical quantities like temperature, humidity, pressure, liquid level, light, ultraviolet light, and gas, the corresponding sensors are called temperature sensors, humidity sensors, pressure sensors, liquid level sensors, light sensors, gas sensors, etc. This naming method makes it easier for users to quickly find the products they need.
Sensors can be categorized by their working principle, including resistive, capacitive, inductive, piezoelectric, electromagnetic, magnetoresistive, photoelectric, piezoresistive, thermoelectric, nuclear radiation, and semiconductor sensors. This allows sensor R&D personnel to conduct inductive analysis and research from a principle and design perspective. Based on the distance between the sensor and the object being measured, sensors can be divided into contact and non-contact sensors. Non-contact sensors can be used to monitor changes in object values in high-risk, high-temperature environments; for example, infrared thermometers allow users to easily measure hard-to-reach or moving targets.
Sensors can be classified into active and passive types according to their function. Active sensors can detect changes in the object being measured caused by the detection signal, or generate a signal by the effect produced by the detection signal in the object being measured. Passive sensors simply receive signals generated by the object being measured itself, such as infrared thermometers commonly used in homes today.
In addition, the measurement range needs to be selected according to the environment in which the temperature and humidity sensor is used. Generally, the temperature and humidity range is -40℃ to +80℃ by default, and the humidity is 0%RH to 100%RH by default. The ultra-high/low temperature range is -100℃ to +200℃. In actual use, the influence of dust, oil and harmful gases should be taken into account, and products with high drift should be selected to ensure that the product can be used for a longer period of time.
Measurement accuracy is the most important indicator of humidity sensor performance. The higher the accuracy, the higher the price. When choosing a product, you should also consider this and choose a product that suits your needs.
