a) Explain the working principle of the right led derived circuit of Figure Qla R2 www to right arm to left arm to right leg RG U1 U2 RS ZR6 R7 Ra Rb R1 www R3 2 R4 Rf 2 2 1 ww U4 U3 Ro +m Vo Figure Qla b) An Instrumentation Amplifier with input impedances of 5 MW between each input terminal to ground is used as the first stage of an ECG machine. If the difference in the skin-electrode impedance is 20 kW and the common mode voltage induced from power lines on the patient's body is 10 mV, determine the magnitude of the 60-Hz interference appearing across the input terminals of the Instrumentation Amplifier. c) For the RLD circuit in Figure Q1a, using the values in (b) (i.e., Idh = 0.2 mA, RG = 50 kW, If Rr= 5 MW and R =25 kW, determine the common mode voltage Vem on the patient's body. (i) (ii) Using this new Vem value from above, calculate the magnitude of the 60-Hz interference appearing across the input terminals of the Instrumentation Amplifier in (b)