22-02-2013, 11:50 AM
To design HPF using OPAMP.
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OBJECTIVE: - To design HPF using OPAMP.
(I) PRACTICAL SIGNIFICANCE: - HPF is used in communication Transmitter and receiver
(II) COMPETENCY/SKILL: - Design and testing.
(III) EXPERIMENT OBJECTIVE: - To design HPF using OPAMP.
(IV) THEORETICAL BACKGROUND: -
High pass filters are often formed simply by interchanging frequency determining resistors and capacitors in low pass filters. That is, a first order high pass filter is formed from a first order low pass type by interchanging components R and C. Fig. Shows a first order high pass butter worth filter with a low cutoff frequency fL. This is the frequency at which the magnitude of the gain is 0.707 times its pass band value. Obviously, all frequencies higher than fL are pass band frequencies, with the highest frequency determined by the closed loop bandwidth of the op-amp.
Since high pass filters are formed from low pass filters simply by interchanging R’s and C’s the design and frequency scaling procedures of the low pass filters are also applicable to the high pass filters.
PROCEDURE: -
1. Now connect the circuit as per diagram.
2. Apply sinusoidal input signal of constant amplitude (Vin) to the input terminal of the circuit.
3. Vary the input frequency from 10 Hz (keep Vin constant) in steps & note corresponding peak to peak amplitude of output (Vo).
4. Calculate voltage gain and tabulate the reading as per observation table.
5. Plot the frequency response curve for the filter and find out the cut off frequency of the filter.