Can you please check if it's correct for me to assume Rm1 = Rm2 = 900k ohms for part D? The other answers use AD8605 to find Rm1 and Rm2 but the question asked to use the ones in the list.

Figure Q1 (a) Figure Q1 shows an amplifier circuit which is used to amplify the output of a thermocouple. The thermocouple has a resistance RTC of 2. Re-draw the circuit to show all sources of DC error. [8] (b) Hence derive an expression for the total DC error, as a voltage referred to the output. Include the effects of both bias and offset cuurents and clearly state any assumptions you make. (c) The thermocouple has a sensitivity of 42VK1. If the output of the amplifier is required to have a sensitivity of 20mVK1, choose suitable values for RI and R2. Discuss carefully why you have chosen the value for R2. What limits the range of values you can choose? [6] (d) The opamp A1 is one of the three listed below (specifications are typical). Choose appropriate values for Rm/ and Rm2 and explain your choice. [6] (e) Define a figure of merit (F.O.M.) for Al and hence compare the opamps below. If the amplifier is required to have an error of less than 0.1K, choose an opamp to use for A1. What effect did the price of the component have on your choice? What effect did the performance of the component have on your choice? [12] Table Q1 Continued overleaf