Active Low pass Filter using Op-Amp Experiment Procedure, Observations, Results and Viva 2023

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Aim :

To study the frequency response of first order low pass active filter using Op-AMP. Determine the cut-off frequency and phase shift using dual trace CRO.

Apparatus :

Dual trace CRO, Dual power supply, OP-AMP 741, signal generator, resistors, capacitor etc.

 

Formulae :

 

Circuit Diagram :

Study first order low pass - Experiment

 

Procedure :

Circuit by – Rajendra Kumar

  1. Trace the circuit and write all components value.
  2. Calculate the cut-off frequency of the filter using the formula.
  3. Study it’s frequency responses over a frequency range of fc/10 to 10fc.
  4. Determine the phase shift of Vo and Vi for any two frequencies in the pass band and at cut-off frequency, using a dual trace CRO.
  5. Plot a graph of Vo against logFin. Determine the cut-off frequency and compare is with the expected values.

Observations :

 

Viva Question and Answers [FAQ] :

1. What is Filter?

Ans : Filter is a device or process that removes some unwanted components or features from a signal.

2. What is Low Pass?

Ans : Pass frequency lower than a certain cutoff frequency.

3. What is Frequency response?

Ans : The dependence on signal frequency of the output–input ratio of an amplifier or other device.

4. Define cut-off frequency?

Ans : In physics and electrical engineering, a cutoff frequency, corner frequency, or break frequency is a boundary in a system’s frequency response at which energy flowing through the system begins to be reduced (attenuated or reflected) rather than passing through.

5. What is phase shift?

Ans : Phase Difference is used to describe the difference in degrees or radians when two or more alternating quantities reach their maximum or zero values.

6. What is Bandwidth?

Ans : Bandwidth is the amount of data that can be transferred from one point to another within a network in a specific amount of time.

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