Why does the Pressure Sensor Make Noise?
A pressure sensor is a device equipped with a pressure-sensitive element that measures the pressure of a gas or a liquid against a diaphragm made of stainless steel, silicon, etc. When using a pressure sensor, there will inevitably be some problems, such as noise. What are the reasons for the noise? It may be caused by the discontinuity of the internal conductive particles, or the shot noise generated by the semiconductor device, etc. Some other reasons will be introduced in detail below.
Causes of noise in pressure sensors
- For the pressure sensor low frequency noise is mainly due to the internal conductive particles appear discontinuous and lead to. In particular, for carbon film resistors, its carbon material often exists inside many tiny particles, particles are discontinuous, in the current flow period, will cause changes in the conductivity of the resistance caused by changes in current, resulting in a similar contact bad flash arc.
- For semiconductor devices generated by the scattered particles of noise, mainly due to changes in the voltage of the potential barrier area at both ends of the semiconductor PN junction caused by changes in the number of charges accumulated in this area, thus revealing the capacitive effect. When the forward voltage is reduced, it makes the electrons and holes broad depletion area, which is equivalent to the capacitive discharge.
- When the reverse voltage is applied, the depletion zone changes in the opposite. When the current flows through the potential barrier area, this change will cause small fluctuations in the current flowing through the potential barrier area, resulting in current noise. Generally in the pressure sensor circuit board electromagnetic components, if interference is generated on many circuit boards have relays, coils and other electromagnetic components, the inductance of its coil and the distributed capacitance of the housing during the smooth flow of electricity to the nearby radiation energy, its energy will produce interference in the nearby circuit.
- Like relays and other components of its repeated work, power on and off will produce instantaneous reverse high voltage, the formation of transient surge current, this instantaneous high voltage on the circuit will produce a large impact, thus seriously interfering with the normal work of the circuit.
In order to reduce the occurrence of these problems of pressure transducer, some things need to be paid attention to when using the pressure sensor, such as to prevent the dross from depositing in the conduit and the contact of the transmitter with corrosive or overheated medium, the pressure guiding tube should be installed in the temperature fluctuation small places, etc.