4.1 Suppose R₁ = R₂(unstrained) = R3 = R4(unstrained) = R (12 marks). a) Which artificial limb movements, (1) bending or (II) extension (R₂ and R4 extended in the same direction),

can we use the Wheatstone bridge in Fig. 4 to evaluate and why? Derive V bridge (as a function of Vin, G, and ) when the limb is bent down as shown in (1). c) What is Vbridge when the limb is extended as (II)? b) d) If we have G = 8.0, Vin = 10V, and = 5 microstrain, what is Vbridg for (a)? 4.2 Now, we bend the limb up as Fig. 5 shows and connect the output nodes Vout,12 and Vout,34 to an instrumentation amplifier (pay attention to the connection) to produce Vout. (18 marks) a) What is the transfer gain K = Vout/Vbridge (as a function of RG, RS, R6, and R₂)? b) What is Vout (as a function of Vin, G, &, and K)? Pay attention to the signal sign. c) If we have G = 8.0, Vin = 10V, &= 5 microstrain, RG = 1 ks, R₁ = 4.5 KQ, R6 = 1 ks, and Ry = 10 k2, calculate Vout and K (K in dB)? d) Suppose the gauge factor has a temperature variation coefficient per Celcius degree (AG/G)/AT = +0.02%/°C. If we have a temperature change from 0 to 100 °C, what are the voltage changes in V bridge and Vout, respectively?