# Lab 3 TF EIM

RC Low-pass filter

# 1-50 kHz filter (20 pnts)

1.) Design a low-pass RC filter with a break point between 1-50 kHz. The break point is the frequency at which the filter starts to attenuate the AC signal. For a Low pass filter, AC signals with a frequency above 1-50 kHz will start to be attenuated (not passed). 2.)Now construct the circuit using a non-polar capacitor. 3.)use a sinusoidal variable frequency oscillator to provide an input voltage to your filter. 4.)Measure the input and output voltages for at least 8 different frequencies which span the frequency range from 1 Hz to 1 MHz.

 Hz Volts Volts

5.) Graph the -vs-

# phase shift (10 pnts)

1. measure the phase shift between and as a function of frequency . Hint: you could use as an external trigger and measure the time until reaches a max on the scope .

# Questions

1. compare the theoretical and experimentally measured break frequencies. (5 pnts)
2. Calculate and expression for as a function of , , and . The Gain is defined as the ratio of to .(5 pnts)
3. Sketch the phasor diagram for ,, , and . Put the current along the real voltage axis. (30 pnts)
4. calculate and expression for the phase shift as a function of , , and graph -vs . (20 pnts)
5. Compare the theoretical and experimental value for the phase shift . (5 pnts)
6. what is the phase shift for a DC input (the limit as frequency goes to zero) and a very-high frequency input?(5 pnts)