Question

A P-type semiconductor strain gauge has a nominal resistance of $1000\Omega$ and a gauge factor of $200$ at ${25}^{o}C$. The resistance of the strain gauge in ohms when subjected to a compressive strain of $100$ microstrain at the same temperature is

• A. $980\Omega$
• B. $1020\Omega$
• C. $1200\Omega$
• D. $800\Omega$

Answer 1

The correct option is A $980\Omega$

$\text{Change in resistance}\left(\Delta R\right)=R_0\times G_f\times ϵ$
$=1000\times 200\times 100\times {10}^{-6}$

$=20\Omega$

Now, since when compressive strain is applied to the P-type semiconductor strain gauge, its resistance get decreased.

$\therefore R_C=R-\Delta R=1000-20\Omega$

$=980\Omega$