A strain gauge is being used to track the strain in a beam, and it forms part of the potential divider circuit shown in Fig. 9.1.
When no strain is applied, the strain gauge has a resistance of $120.0\,\Omega$. If the strain becomes $\varepsilon$, the resistance rises to $121.5\,\Omega$.
(a)[3]
Calculate the potential difference between A and B on Fig. 9.1 when the gauge strain is $\varepsilon$.
(b(i)-1)[2]
Complete the inverting-amplifier circuit on Fig. 9.2.
(b(i)-2)[1]
On Fig. 9.2, place the letter P on the positive terminal of the voltmeter.
(b(ii))[2]
Propose suitable values for the resistors you have drawn in Fig. 9.2. Annotate Fig. 9.2 with those values.
(b(i)1)[2]
Finish the inverting-amplifier circuit on Fig. 9.2.
(b(i)2)[1]
On Fig. 9.2, put the letter $P$ on the positive terminal of the voltmeter.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Bridge output change calculated to be $6.2\,\text{mV}$ (allow $6\,\text{mV}$).” …