load cell wheatstone bridge R values

Sensors Force & Weight
1

I’ve tried measuring resistances among the terminals of a 4-wire load cell, and get results I wasn’t expecting.

I assumed that the symmetry of the Wheatstone bridge should mean that, at rest, resistance top to bottom (red to black) would be the same as side-to-side (white to green). These measurements should reveal the values of the Wheatstone bridge’s resting R values.

I get 1k for each total, implying that each internal resistance (at rest) also is 1k (since we have two paths in parallel, each of 2 R value).

So far, so good.

But when I measure red to white, or green, or black to white or green, I get not 1k but 750 ohms.

So, am I wrong to think the load cell’s innards are as simple as a Wheatstone bridge, with its 4 R’s being the 4 strain gauges?

Thank you,

Tom

2

Never mind: I see that the values make sense: white to green is 1k parallel the other, longer path, which is 3k. Hence, 3/4k result.

Sorry to waste your time with an easy question.