30-06-2012, 02:20 PM
To plot the frequency response of constant-k low pass filter.
To plot the frequency response of constant-k low pass filter..docx (Size: 25.59 KB / Downloads: 47)
THEORY:
A low pass filter is one which passes low frequencies up to cut-off frequency and attenuates the rest of frequencies.
A network, either T or П , is said to be of the constant- k type if Z1 & Z2 of the network satisfy the relation:
The constant- k, T or П type filter is known as the prototype because other more complex networks can be derived from it. Also for both the networks:
PROCEDURE:
1. Connect sine wave generator at the input of the filter. Adjust sine wave amplitude to 5Volt p-p. Keep the input voltage constant throughout the experiment.
2. Connect CRO at the output of the filter.
3. Vary the input frequency from minimum to 10KHz in proper steps in sine wave generator and every time note the input frequency and corresponding output voltage from the CRO in the observation table.
4. Plot the graph between input frequency & Output Voltage taking input frequency (in Hz) on x-axis and output voltage (in Volts) on y- axis on semi log graph paper.
5. Calculate the cut-off frequency from the formula as well as from the graph.