Virtual Simulation



Case Study



Aim:


To design and study the open loop gain from Inverting Amplifier circuit.

Components required:


   Function generator, CRO, Regulated Power supply, resistor, capacitor, 741 IC, connecting wires.


Vlab Specifications Taken:


Inverting Amplifier circuit design has been implemented on the virtual breadboard using following specifications:

  • Power Supply: +10v and -10v
  • Function generator: Selected wave with following specifications:
Frequency = 50Hz Amplitude: 750mV, 850mV, 900mV, 950mV, 1V, 2V. Duty cycle = 50%
  • Resistor R2: 10.38K
  • Resistor R1: 1.369K



Theory:


An inverting-amplifier circuit is built by grounding the positive input of the operational amplifier and connecting resistors R1 and R2, called the feedback networks, between the inverting input and the signal source and amplifier output node, respectively. With assumption that reverse-transfer parameter is negligibly small, open-circuit voltage gain Av, input resistance Zin and output resistance Zo can be calculated.



Inverting Amplifier configuration of an op-amp


Procedure:


  1. Connect the circuit as shown in the circuit diagram.
  2. Give the input signal as specified.
  3. Switch on the power supply.
  4. Note down the outputs from the CRO
  5. Draw the necessary waveforms on the graph sheet.


Observations:


  1. Observe the output waveform from CRO. An inverted and amplified waveform will be observed.
  2. Measure the input and output voltage from the input and output waveform in the CRO.
  3. Calculate

  4. Compare the theoretical voltage gain from the above equation with the experimental value obtained by dividing output voltage by input voltages observed.
  5. Observe outputs of the inverting amplifier circuit using different input waveforms.


VLab Observations Obtained:



    1. After Clicking on Open function generator icon on the left of the Vlab live environment page, set the frequency, amplitude and the type of waveform on function generator.
    2. Select sine wave and then set frequency 50Hz



    1. Select amplitude. Optimal example amplitude considered is 890mV.




    1. Check graph



    1. Circuit has been designed on the virtual breadboard with the help of procedure.



    1. Then on clicking on Run icon, the output waveform generated and the input can be observed on the CRO. CRO web page can be opened using icon oscilloscope at top left on the live experiment page.




    1. Click on measure.Then one can observe options like source, select, measure.
      • Click on source and select 4 i.e. the input wave.
      • Click on select and select the parameter to be measured for example select frequency or amplitude.
      • Click on measure to get the frequency and amplitude of the input waveform.

      It comes out to be Frequency: 50Hz, amplitude: 1.73V






    1. Now observe the amplitude of the output waveform generated.



    The output voltage comes out to be 11.9V.




Calculations:



    1.Calculate experimentally observed voltage gain Av using observed Vo& Vin from CRO.



      2.Theoretically voltage gain is given by:






      3.Table representing voltage gain theoritically and experimentally at different amplitude input waveforms.



    Input Voltage Gain (Th.) Gain (Pr.)
    2V 6.35 7.4
    1V 6.57 7.4
    890mV 6.88 7.4
    850mV 6.71 7.4
    750mV 6.47 7.4


    1. Observe and measure the gain of the non inverting amplifier at different input voltages and with different waveforms.




Result:



Hence the opamp can configure as inverting amplifier circuit as observed from the output waveforms.

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