# Operating a load cell below excitation voltage

I currently have this load cell, which has a 10V excitation voltage. However, there is a very nice/convenient load cell amplifier that works with an excitation voltage of 5 VDC.

What are the consequences of operating a cell at a voltage lower than the normal excitation? Just increased noise in the signal?

The load cell you linked to has a line item on the specs that says "Output: 2 mV/V nominal". Let's just say that you picked the version with 100 lbf full scale output. What that means is this: if you use a 1 V excitation, you'll get a response something like this

Load    Output
0 lbf   0 mV
50 lbf   1 mV
100 lbf   2 mV


Now if you use a 10 V excitation, you'll get this

Load    Output
0 lbf   0 mV
50 lbf  10 mV
100 lbf  20 mV


So if you want to use a 5V excitation, it will work perfectly fine. Just do the math on the expected output.

Regarding your comment on noise. The signal to noise ratio will be likely be better with a higher excitation voltage. So yes, if you use 5 V instead of 10V, you probably have a slightly worse signal to noise ratio. Depends on your application and the precision required as to whether that will be acceptable.

• So given that, this product works fine for my purpose? I'm having trouble navigating the selection process for hooking up a load cell to a pc correctly, so a catch all system (while probably suboptimal) may meet my needs... Aug 12 '18 at 22:58
• I have not used that particular product, but it looks like it should work. Aug 13 '18 at 1:41