Can you guess the stress in a 1- ohm resistance change?
The story for strain gage electrical resistance goes back many decades. Originally, 120 Ω was used, because that value matched the impedance characteristics of the available instrumentation, and was a convenient enough value to manufacture in common sizes using 25 µm diameter wires. Modern instrumentation eliminates the requirement for 120 ohms, and allows for much higher resistances, if needed (for example, 5000 Ω).
