Lab 5 - EE 420L
Lab Report
For the first part of the lab, students were tasked at calculating the frequency response of the following circuit.
Image 1: Given circuit that frequency response is calculated from.
Image 2: Frequency response calculated from circuit given
What can you neglect to simplify the calculation?
The 100k resistor can be ignored as it is so large compared to R1 that it is essentially an open.
Image 3: Frequency response calculated ignoring R2
Does the circuit work if you remove the 100k? why or why not?
The circuit will not work as the DC offset would be too much and the signal would most likely clip at one if not both sides of the signal.
Does the 100k have much of an effect on the frequency response?
Since we can essentially ignore the 100k in the origianl equation of calculating frequency response it should have little effect if removed.
Verify the calculations with experimental results.
For all of the following photos the green wave is yellow and the output wave is blue
Show that the inpur and output of the integrator have the same peak values at the unity gain frequency.
Image 4: Oscilloscope reading of circuit at unity gain.
As the frequency is increased the rails of the op amp are hit and clipping starts to increase.
Image 5: Oscilloscope reading of circuit at frequency higher than unity gain.
Is the phase shift between the input and the output what you expected? Why or why not?
The phase shift is what we expected of 90 degrees as we expected from the hand calculations.
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Image 6: Triangle wave circuit created.
Image 7: Capacitance and resistance values calculated from circuit.
The trade off that was made is that the higher resistor value will give a smaller capacitance, the values choosen were to fit the capacitors and resistors that were in the lab. The next step was to take the values that were decided on previously and sim the circuit using LTspice.
Image 8: LT spice simulation of created trianlge wave circuit.
Unlike the simulation the triangle wave that was made experimentally did not give a perfect triangle wave but rather had a large shoot off point at the peaks of the output.
Image 9: Oscilloscope reading of triangle wave circuit.