Aim :
To study the frequency response of second 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, capacitors etc.
Formula :
Circuit Diagram :
Procedure :
Circuit by – Rajendra Kumar
- Trace the circuit and write all components value.
- Calculate the cut-off frequency of the filter using the formula.
- Study it’s frequency responses over a frequency range of fc/10 to 10fc.
- 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.
- Plot a graph of Vo against logFin. Determine the cut-off frequency and compare is with the expected values.
Obs/Cal/Graph/Result :
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 higher 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.