A load cell is used to measure the force of a weight scale. The strain gage and the electronic circuit is bought from the manufacturer. It is desirable to understand

the process to read the loadcell value. 1. 15 pts – The load cell is based on a half-bridge Wheastone circuit as shown on the figure. Determine the expression of the output voltage Vo relative to the variable resistance Rg. + deltaR and the other elements of the circuit. Assume that R1 = R2 =RG= 100 ohms 2. 15 pts – The battery voltage Vex =12v Plot the output voltage Vo for a range of delta R E [-1; 1]ohms. You may use Matlab/Octave/Excel to plot the graph.What is the range of the output voltage?= 12V. 3. 15 pts – The range of the output voltage Vo is rather small and has a negative proportional relationship with deltaR.Draw an operational amplifier circuit that invert the sign and multiply the output voltage. Select the resistances of the OA circuit, so that the range of the output voltage of the OA circuit is [-2.5; 2.5]V. 4. 15 pts – A microcontroller cannot read negative voltage. Draw an OA circuit is to add2.5V to the previous output circuit, so that the output range becomes [0; 5]V. Specify the value of the resistances used.