A capacitive pressure sensor is a pressure sensor based on the capacitive principle, which can measure the pressure of a gas or liquid. Capacitive pressure sensors are classified in a variety of ways, the most common of which is to classify them according to how they work. According to the working principle, capacitive pressure sensors can be divided into three types: variable area type, variable medium type and variable pole distance type.
One of the most common types is a variable area capacitive pressure sensor that measures pressure by changing the capacitance by changing the area between the plates of the capacitor. When pressure is applied to the sensor, the diaphragm inside the sensor deforms, causing the distance between the plates to decrease or increase, thus changing the capacitance. Since the capacitance is directly proportional to the pressure, the pressure can be measured by measuring the capacitance.
Variable dielectric capacitive pressure sensors measure pressure by changing the capacitance by changing the medium between the capacitor plates. Such a sensor usually consists of a liquid-filled container and an electrode, and when pressure is applied to the sensor, the density of the liquid medium changes, thus changing the capacitance. Since the capacitance is directly proportional to the pressure, the pressure can be measured by measuring the capacitance.
Pole-ranging capacitive pressure sensors measure pressure by changing the capacitance by changing the distance between the capacitor plates. This type of sensor usually consists of a fixed electrode and a movable diaphragm that deforms when pressure is applied to the sensor, changing the distance between the plates. Since the capacitance is directly proportional to the pressure, the pressure can be measured by measuring the capacitance.
To sum up, the working principle of capacitive pressure sensors is mainly to measure pressure by changing the capacitance. Different types of sensors, although different in structure and operating principle, are all designed based on the principle of capacitance. In practice, it is necessary to select the right sensor type according to the specific use environment and requirements.