a. Use a capacitor, a resistor and an operational amplifier circuit to design an active first order low pass filter which passes frequencies that human can hear (below 15kHz). Show all the calculations required to find the values of all the passive components used in this amplifier circuit and sketch a circuit diagram for your design. Hint: assume the required value of capacitor. It should be less than 0.1 μF (for better frequency stability) then calculate the value of R.

b. Use MultiSim to simulate and test the circuit you designed. Show a printed Oscilloscope and bode plotter displays for the output of the circuit. Show all the component values.

A customer wants to automate a pressure measurement, which requires converting the output of the pressure transducer to a computer input. This conversion can be done using a standard integrated circuit called an Analogue-to-Digital-convertor (ADC). The ADC requires an input voltage between (0) V and (10) V while the pressure transducer output varies between (-250) mV and (+250) mV. (Shown in Fig 1)

Fig 1

You are required to design a circuit to interface the pressure transducer with the ADC. This circuit translates the range (-250) mV and (+250) mV to the range (0) V and (10) V.

1. Establish a simple relationship between V1 and V2 shown as a linear equation. The specifications states that:

-250mV ≤ V1 ≤ 250 mV 0V ≤ V2 ≤ 10V

2. Generate a plan to design a circuit having input voltage V1 and output voltage V2. These voltages (V1 and V2) should be related by the linear equation established in (a). Use operational amplifiers that are biased using +15V and - 15V. Draw a block diagram for your plan.

3. Draw a circuit diagram for the interface circuit. Show all the component values.

4. Use MultiSim to simulate the circuit you designed. Show a printed Oscilloscope display for the output of the circuit. Show all the component values.