A novel electronic PS pressure sensor 3

ΔV=ΔRI (2)

This Δ V relative pressure exhibits almost completely linear characteristics, only changing with temperature.

Design of peripheral circuits  diode

Figure 4 shows an example of the peripheral circuit design of a PS pressure sensor, in which a constant current source is used to drive the pressure sensor. Due to the small output voltage when the bridge circuit is unbalanced, it is necessary to use  diode  operational amplifiers IC1b and IC1C for amplification. VR1 in the figure represents bias adjustment, VR2 represents pressure sensitivity adjustment, VR3 represents output voltage adjustment without pressurization, and C1 and C2 are used to remove noise. In addition, if the power supply voltage fluctuates, it will cause changes in the output voltage, so it is necessary to provide a stable power supply to the circuit. Figure 5 shows an application example of PS pressure sensor in a fully automatic washing machine. As shown in the figure, using an air chamber, the changes in water pressure at different water levels can be detected as changes in air pressure, so that the washing machine can automatically stop injecting water at the set water level.c'c'c