【Help】Sensor selection for a certain op amp circuit

ddasd

【Help】Sensor selection for a certain op amp circuit [Copy link]

 

To explain briefly, I work in industrial control, and my knowledge of electronics and analog circuits is limited to professional courses such as analog electronics and digital electronics.

Someone in the company designed a PCB board for signal acquisition, but we couldn't buy the sensor used in the design. I would like to ask the experts if we can tell what kind of sensor input is based on the electrical schematic.

(I bought a variable resistor type FSR406. There was no schematic diagram at the time. Later, after getting the information and checking online, I felt that it was a piezoelectric film type. But I don’t know what specific parameters are required.)

fxyc87

This is a voltage follower, that is, the output is the same as the input voltage, and is used for high impedance signal input

fxyc87

Then R157 and R158 divide the voltage to 2/3 of the original voltage

hehekai

Learned

maychang

A sensor is a device that converts non-electrical quantities (mechanical, temperature, optical, etc.) into electrical quantities.

What kind of sensor it is should be determined by what quantity you want to convert into electrical quantity, which cannot be seen simply from the electrical schematic.

ddasd

fxyc87 Published on 2021-11-30 10:56 This is a voltage follower, that is, the output is the same as the input voltage, and it is used for high impedance signal input

So, as long as I set the voltage between 0V and 3V, it can satisfy the signal switch input?

ddasd

maychang posted on 2021-11-30 12:37 A sensor is a device that converts non-electrical quantities (mechanical, temperature, optical, etc.) into electrical quantities. What kind of sensor is it?

But I don't even know what type of electrical quantity this connector should input.

annysky2012

I really can't tell.

maychang

ddasd posted on 2021-11-30 12:47 But I don’t even know what type of electrical quantity to input into this connector

In your circuit, the input is obviously a voltage, and the internal resistance of the sensor is relatively large, otherwise R46 would not be as large as 10 megohms.

maychang

ddasd posted on 2021-11-30 12:47 But I don’t even know what type of electrical quantity to input into this connector

In addition, considering that the capacitance of C70 is 10 nanofarads, the input signal frequency will not be high, at most a few Hz. This is a slowly changing signal.

qwqwqw2088

FSR406 reference

压力传感器 FSR406数据手册.pdf (963.8 KB, downloads: 5)

2021-11-30 16:24 上传

点击文件名下载附件

Gen_X

It should be a piezoelectric sensor with a very high input impedance, so a voltage follower method is used to process the signal.

埋土书生

High impedance voltage output signal

Fred_1977

The signal input buffer circuit is only used for impedance conversion.