Connecting wires to load cells

[engr_joni_ee]

Hi,

I have four load cells. I am wondering how to connect them in a bridge. The resistance between black and white cable is 2 k ohm. The resistance between red and white cable is 1 k ohm. I just push the middle part, I don't see big change in the resistance.

 

[wwfeldman]

so you have four items like the picture?
who is the manufacturer, what is the manufacturer's part number,
and what does the data sheet say about the connections
of the various wires to whatever is inside the metal part?

 

[engr_joni_ee]

Yes, I have four identical resistors. They are from human weighing machine. I guess each is rated up to 30 Kg. I am just wondering how much change in resistance in ohms each can have by putting load on them. I need some numbers as reference.

 

[FvM]

Standard load cells (4-wire full bridge) have 1 - 3 mV/V output at rated load.

 

[KlausST]

Hi,

What I did:
* internet search "load cell"
* looking for similar pictures than yours
* looking for information given with pictures
*;the second one gave "1 +/- 0.15 mV / V".

It took about 10 seconds... (not a complete day)

It also says "half bridge" ... this explains three wires instead of four wires of a full bridge. ...and less precision....

Klaus

 

[engr_joni_ee]

Thanks for sharing info. Actually I am looking for load cells up to 5 kg. I am not sure if they exist. I would be great if they have large change in resistance with applied load, for example 1 K ohm at 0 Kg and 1.1 K ohm or 1.05 k ohm at 5 kg.

 

[KlausST]

Hi,

I'd say: no chance. Read what FvM wrote.

Consider to add an amplifier.

Klaus

 

[ZASto]

Search for HX711, you will find a lot of interesting stuff