Enter your student identification number (S.I.D.) in the grid below. The individual digits of this are used in the specifications that follow. In all cases if a specific digit is a ‘0’, it should be interpreted as if a ‘10’. A B

Task details

Enter your student identification number (S.I.D.) in the grid below. The individual digits of this are used in the specifications that follow. In all cases if a specific digit is a ‘0’, it should be interpreted as if a ‘10’.

Part A: Ideal op-amp design and simulation [5 marks]

1. Design a non-inverting amplifier based on an operational amplifier gain element to provide a gain equal to digit ‘G’ in your SID and with an (external) input impedance equal to ‘F’ kW. The feedback resistor of the operational amplifier should be equal to 10 × ‘E’ kW. The supply voltage should be fixed at ±15V.

Insert the circuit diagram here: [2 ½ marks]

1. Simulate the design on Multisim and include details of simulation circuit and results that demonstrate its input impedance and gain. You are recommended to use the 3-terminal virtual operational amplifier model within Multisim and set its simulation properties to approximately ideal. [2 ½ marks]

(Important: Some model issues have been noted when working with Multisim version 10.0)

Part B: Non-ideal amplifier implementation and simulation [10 marks]

1. If the sum of all digits of your S.I.D. amount to an even number, the real (non-ideal) specifications of the operational amplifier used to implement the design are that it has an (internal) input impedance of ‘D’ kW, an (internal) output impedance of ‘C’/10 kW and a finite gain (Open loop gain) of ‘B’/10 kV/V. Otherwise the finite gain is ‘A’/10 kV/V. The gain should roll off at a rate of -20 dB/decade after ‘B’ Hz. Explain how you can model this on the Multisim op-amp including evidence of how you do this practically.

[5 marks]

1. Improvise the simulation from part A and present results to show what the gain, input impedance and gain roll-off of the circuit under the non-ideal conditions given. [5 marks]

Part C: Theoretical analysis and comparison [10 marks]

Undertake a systematic theoretical analysis of the amplifier design in the non-ideal condition to determine its expected input impedance and gain with proper equivalent circuit diagram. How do the theoretical calculations compare to the simulated results under non-ideal conditions? Discuss any differences. [10 marks]

(Note: it is much harder to analyse the non-ideal amplifiers than ideal ones. You are recommended to draw an equivalent circuit and analyse it using nodal analysis. Since we are interested in observing small errors it is important that all numerical calculations are performed with adequate precision. The analysis will not be tolerant of careless errors – be sure to check each stage carefully.)

Part D: Application of non-ideal amplifier in instrumentation amplifier [25 marks]

1. Apply the non-ideal amplifier developed in part B to construct a classical triple op-amp instrumentation amplifier. The gain of the instrumentation amplifier is required to be 10 ´ ‘G’. The feedback resistor in part A is expected to be found in the feedback path of all op-amp in the design. The input bias current, I_IB, of all the discrete op-amps is 10 ´ ‘C’ nA.
   1. Determine the values of the remaining resistors in the design circuit diagram that can be conveniently sourced from E24 standard resistor series. [4 marks]
   2. Estimate the magnitude of error introduced by the input bias current to the output signal. [4 marks]
   3. Suggest a way to minimize the error introduced by the input bias current. [8 marks]

1. Estimate the highest input signal bandwidth (f_p or w_p) that do not cause output distortion should the corresponding D.C. input signal magnitude (V_in(D.C.)) do not cause output to saturate. All estimation should be validated. [9 marks]