strain gauge questions

I have a couple of general questions about strain gauges

  1. I notice that they come in several ohm'ages 150, 350 , 1000 what is the difference?

  2. I notice there are full bridge strain gauges which I assume fills out the 4 corners of the wheatstone bridge but it seems to eliminate the added signal produced by having 2 stretched and 2 compressed when a force is added. I must be missing something in my understanding.

thanks steve

1 lower resistance -> greater current -> better immunity to noise

2 From +power: one stretched -> A -> one compressed -> -power and one compressed -> B -> one stretched -> -power

thanks, further question about #1 does higher resistance give more sensitivity with the cost of more noise?

s

thanks, further question about #1 does higher resistance give more sensitivity with the cost of more noise?

s

no. The resistors are connected as voltage dividers (Wheatshone bridge) Resistance value doesn't really matter. (1k..2k isn't unusual in the small scale sensors)