**A piezo-electric material used to construct a precision scale to measure loads with step of no more than 0.05 N. the scale is made of a quartz (G= 0.055 V.m/N) disk having diameter of 3 cm and thickness of 0.2 mm. the voltage detector used to read the output voltage has a resolution of 1.25 mV. To achieve this, we can install an inverting amplifier with resistance ratio R,/R = 1.607 in an inverting amplifier with resistance ratio R,/R. *1.372 an inverting amplifier with resistance ratio R,/R. *1.8674 O an inverting amplifier with resistance ratio R/R = 2.187 in in **Voltage sign is important