ELEC 101, Spring 2005
Prof. Rich Kozick

Laboratory 7: Frequency Response and Bode Plots

Objective:

We will measure the frequency response of low-pass, band-pass, and high-pass filters. The results will be presented on Bode plots. In Lab 8, we will compare the measured results with analytical formulas, and we will also use these filters to build an audio equalizer.

Lab Activities:

Please complete all of the activities for one circuit before going on to the next circuit.

  1. Collect frequency response data in your lab notebook for the frequency range from 10 Hz to 20,000 Hz. At minimum, collect data at the frequencies 10, 20, 50, 100, 200, 500, 1000, 2000, 5000, 10,000, and 20,000 Hz. You may want to take more data in the "knee" of the frequency response.

    For each frequency, measure the amplitude of the input and output voltage sine wave.

  2. Produce a Bode plot of your data:
    20 log10 (Output amplitude / Input amplitude) versus frequency on a logarithmic scale
Save your circuit components and bring them to lab next week.

Question:

Associate the following names with the appropriate circuit: low-pass, band-pass, high-pass filter.