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

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

 

Non-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 R₂:10.38

·         Resistor R₁: 1.369K

 

The operational amplifier can also be used to construct a non-inverting amplifier with the circuit indicated below. The input signal is applied to the positive or non-inverting input terminal of the operational amplifier, and a portion of the output signal is fed back to the negative input terminal. Analysis of the circuit is performed by relating the voltage at V₂ to both the input voltage V_in and the output voltage V_o. 
The output is applied back to the inverting (-) input through the feedback circuit (closed loop) formed by the input resistor R₁ and the feedback resistor R₂. This creates �ve feedback as follows. Resistors R₁ and R₂ form a voltage-divider circuit, which reduces V_o and connects the reduced voltage V₂ to the inverting input. 

Figure 1: Non-Inverting Amplifier configuration of an op-amp

 

 

1.     Connect the circuit as shown in the circuit diagram.

2.     Measure the input and output voltage from the input and output waveform in the CRO.

3.     Switch on the power supply.

4.     Note down the outputs from the CRO

5.     Draw the necessary waveforms on the graph sheet.

 

 

1.     Observe the output waveform from CRO. A non-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.

 

 

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

 

 

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

 

 

4.     Check graph

 

 

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

 

 

6.     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.

 

 

7.     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: 1.94V

 

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

 

 

The output voltage comes out to be 17.3V.

 

1. Calculate experimentally observed voltage gain A_v using observed V_o & V_in 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	9.41(clipped)	8.4
1V	8.91(clipped)	8.4
900mV	8.49(clipped)	8.4
890mV	8.35	8.4
850mV	9.12	8.4

 

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