Lab 4 RS
- RC High-pass filter
1-50 kHz filter (20 pnts)
1. Design a high-pass RC filter with a break point between 1-50 kHz. The break point is the frequency at which the filter's attenuation of the AC signal goes to 0(not passed). For a High pass filter, AC signals with a frequency below the 1-50 kHz range will be attenuated .
- To design low-pass RC filter I had:
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.
5. Graph the -vs-
phase shift (10 pnts)
- 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 .
See question 3 about my phase shift measurements
1. Compare the theoretical and experimentally measured break frequencies. (5 pnts)
Theoretical break frequency:
The fit line equation from the plot above is. From intersection point of line with x-axis we find:
The error is:
2. Calculate and expression for as a function of , , and .(5 pnts)
Dividing second equation into first one we get the voltage gain:
And we are need the real part:
3. Compare the theoretical and experimental value for the phase shift . (5 pnts)
The experimental phase shift is
The theoretical phase shift is
4. Sketch the phasor diagram for , , , and . Put the current along the real voltage axis. (30 pnts)
5. What is the phase shift for a DC input and a very-high frequency input?(5 pnts)
Because a DC circuit doesn't have any oscillation there are no any phase shift.
For a very high frequency input the phase shift is 0 (see plot in question 6)
6. Calculate and expression for the phase shift as a function of , , and graph -vs . (20 pnts)
From the phasor diagram above (question 4) the angle between vectorsand given by