Applicable to Buick LaCrosse GL8 Saab Oil Pressure Sensor 12570798

So what are the main reasons for the zero drift of the pressure sensor?

First, there are bubbles or impurities in the adhesive layer of the strain gauge.

Second, the strain gauge itself is unstable.

Third, there are virtual solder joints in the circuit.

Fourth, the stress release of the elastomer is incomplete; In addition, it is also related to magnetic field, frequency, temperature and many other things. Electric drift or some drift will exist, but we can narrow its scope or correct it in some ways.

Zero thermal drift is an important index that affects the performance of pressure sensor, and it has been widely paid attention to. Internationally, it is believed that the zero-point thermal drift only depends on the inequality and temperature nonlinearity of the force-sensitive resistor, but in fact, the zero-point thermal drift is also related to the reverse leakage of the force-sensitive resistor. In this regard, polysilicon can absorb heavy metal impurities in the substrate, thus reducing the reverse leakage of the force-sensitive resistor, improving the zero-point thermal drift and improving the performance of the sensor. What other ways are there to reduce and correct the electric drift?

Apart from affecting the measurement accuracy and reducing the sensitivity of pressure sensors, what other important effects does zero drift have?

The so-called zero drift refers to the phenomenon that when the input of the amplifier is short-circuited, there is an irregular and slowly changing voltage at the input. The main reasons for zero drift are the influence of temperature change on transistor parameters and the fluctuation of power supply voltage. In most amplifiers, the zero drift of the previous stage has the greatest influence, and the more stages and amplification factors, the more serious the zero drift is.

The magnitude of drift mainly depends on the selection of strain materials, and the structure or composition of materials determines its stability or heat sensitivity. It is also very important to process the selected materials. Different processes will produce different strain values, and the key lies in the stability of the bridge value or the change of the process law after some aging adjustment.

There are many ways to adjust the drift, which are mostly determined by the conditions or production requirements of manufacturers. Now most manufacturers control the zero drift very well. Temperature adjustment can be compensated by internal temperature resistance and heating zero sensitivity resistance, aging and so on.

For the transformer with circuit conversion, the drift of the circuit part can be compensated by selecting good components and designing more suitable circuits.

The strain material should be a material with high sensitivity and small temperature change.