Now there are a variety of pressure sensors on the market for equipment engineers to choose from. Among them, capacitance and Piezoresistance pressure sensors are the most widely used.
Capacitance pressure transducer is a kind of pressure sensor which uses capacitance as sensitive element to change the measured pressure into capacitance value. Capacitive transducer for pressure measurement generally uses a circular metal film as an electrode of the capacitor. When the film is deformed due to pressure, the capacitance formed between the film and the fixed electrode will change, and the electrical signal related to the voltage can be output through the measuring circuit.
Piezoresistance pressure sensor is mainly based on piezoresistive effect. Piezoresistive effect is used to describe the resistance change of materials under mechanical stress. The pressure of the measured medium acts on the diaphragm of the sensor directly, which makes the diaphragm produce a micro displacement proportional to the pressure of the medium, and changes the resistance value of the sensor. The change is detected by an electronic circuit, and a standard measurement signal corresponding to the pressure is converted and output.
| Piezoresistance Sensor | Capacitance Transducer |
| Performance
·The earliest and most widely used type of pressure sensor. ·simple construction, low cost and good durability. ·Sensors must be powered, which makes them unsuitable for low-power or battery operating systems. · When measuring the micro differential pressure within 10KPA, the sensitivity and accuracy are not high enough, and it is easy to drift。
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Performance
· Because there is no direct current flowing through the capacitors, they are essentially low-power. ·The capacitor elements are mechanically simple and robust and are very adaptable to overpressure conditions. ·Ideal for low voltage applications and quite harsh environments. ·Capacitance Transducer has low hysteresis and good repeatability. The temperature sensitivity is also very low. |
