- 4 Design Of Differential Amplifier In A Particular Application It Is Necessary To Implement A Desired Input Output Rela 1 (208.18 KiB) Viewed 12 times
4 Design of Differential Amplifier In a particular application, it is necessary to implement a desired input-output relationship given by Equation 4.1. Vout = 2VB - 40A (4.1) (a) Design a circuit using only one Op-Amp circuit that realizes this relationship, using configuration of Figure 2.1(a). [10%] (6) Design a circuit using two-cascaded non-inverting Op-Amp circuits that realizes this relationship, using configuration of Figure 2.1(b). [10%) 5 Design of Instrumentation System This section is dedicated to Analogue Signal Processing and Conditioning circuit design. Unlike circuit analysis, where you are asked to find the single correct input-output relationship for a given circuit configuration, circuit design asks you to create a circuit that will realize a desired input-output relationship. The design problems rarely have a unique solution, since there are usually many Op-Amp circuits that can meet the design objective. Then, which is the better or best design solution? Sometimes the choice is obvious; at other times, it is not. Making the right choice is the highest level of thinking, the art of making smart engineering decisions. The starting point in instrumentation system design is the transducer. In many instrumentation systems, the transducer is known and is assumed linear over the desired range of measurements. The desired output is also assumed linear. The task is to design the interface circuit between the input and output. The input transducer generates an electrical signal that describes some ongoing physical phenomenon. The transducer signal is processed by Op-Amp circuits and provided to an output for observation, recording, and further processing by an analog- to-digital converter and other output devices. See Fig. 5.1. Transducer Amplifier ADC Digital Output Figure 5.1: Instrumentation System 5.1 Measurement System Design [30%] A resistive transducer uses a sensing element whose resistance varies with temperature. For a NTC thermistor, the resistance varies non-linearly with temperature. This transducer is to be included in a circuit to measure temperatures in the range from 25°C to 85°C. The circuit must convert the transducer resistance variation over this temperature range into an output voltage in the range from 0 V to 10 V. Verify your design using Multisim. 5 Figure 5.2 shows the measurement and signal-conditioning model [2]. In this case, the entire system is to be developed, from selecting the NTC Thermistor to designing the signal conditioning. The detailed design guideline is outlined in the prescribed textbook, Process Control Instrumentation Technology, 8th Edition, by Curtis D. Johnson, Chapter 2, Section 6, page 101. Refer to Appendix C and D Process Cmex max bmas Holz Sensor Signal conditioning Cmin min bmin Figure 5.2: Model for measurement and signal conditioning objectives [2].