Capacitance weighing sensor's faults

No matter what the sensor has its own advantages and disadvantages, the weighing sensor is the same, it is mainly used to quality signals into electrical signals, the advantages of capacitance sensor is low power consumption, low cost, what are the disadvantages of it, we come to understand in detail. Disadvantages: high output impedance, low load capacity
Capacitance Cooling Temperature Sensor capacity by the electrode geometry restriction very difficult to do, generally tens to hundreds of micro method, even only a few micro method. Therefore, the output impedance capacitive weighing sensor is high, so the load capacity is poor, vulnerable to outside interference produced unstable phenomenon, serious and even unable to work. We must take shielding measures properly, to design and the use of inconvenience. Capacitance sensor also requires insulation resistance value is extremely high, otherwise the insulation performance of part as bypass resistance and affect the instrument, so we should also pay special attention to the surrounding environment such as temperature, cleanliness, etc.. If the use of high frequency power supply, can reduce the output capacitance weighing sensor resistance, but the high frequency amplifier, sensor than low frequency complex, and the effect of parasitic capacitance, is not easy to ensure the stability of the work. Two shortcomings: the output characteristics of output characteristics of nonlinear capacitance weighing sensor is nonlinear, although the use of differential type to improve, but can not be completely eliminated.Engine Coolant Temperature Sensor for other types of only ignores the edge effect of electric field, the output characteristics is linear. Additional capacitance or the edge effect will be directly superimposed sensor capacitor, the output characteristics of nonlinear. Disadvantages: three parasitic capacitance effect of initial capacitor capacitance weighing sensor is small, and the lead capacitance, electronic circuit connected with the sensor and the electronic circuit of the stray capacitance and inside Coolant Temperature Sensor plate and the surrounding conductors capacitors and other so-called missing large parasitic capacitance, not only reduces the sensitivity of the sensor, and the capacitance is often random variation the instrument, work is not stable, influence the accuracy of measurement. So the cable selection, installation, connection method has strict requirements. For example, with good shielding property, its small distributed capacitance of high frequency electric wire as the lead, lead is thick and short, to ensure the instrument stray capacitance is small and stable and so on, otherwise it can not guarantee the high measurement precision. It should be pointed out that, along with the material, technology, electronic technology, especially the rapid development of technology, the capacitance weighing sensor has been developing and constantly overcome shortcomings. The capacitance sensor is becoming a high sensitivity, high precision, low pressure sensor in dynamic, and some special measurement has a promising.