# Homework Help: Resistance Temperature Detectors Question

1. Oct 31, 2007

### pcdoctor

1. The problem statement, all variables and given/known data
An RTD has a (wierd looking a) (20'c) = 0.004'C-1.
If R = 106 Ohms at 20'c find the resistance at 25'c

2. Relevant equations

R=Ro(1 + (wierd looking a)(T-To))

Answer should come to 108.12 Ohms

3. The attempt at a solution

20 / 106 = 0.1886 * 25 X

2. Nov 1, 2007

### George Jones

Staff Emeritus
What do you think $R_0$ and $T_0$ equal?

3. Nov 1, 2007

### pcdoctor

I managed to do it in the end

Hi,

I had another go at it and i got the correct answer

Sometimes you have to look at things twice.

I cannot do this one:

A strain gauge has GF = 2.14 and a nominal resistance of 120 Ohms. Calculate the resistance change resulting from a strain of 144 um/m.
Any help would be great.

4. Nov 1, 2007

### George Jones

Staff Emeritus
Great!

What is the relevant equation? Once you have this, I think it's just a matter of plugging in the numbers.