EE 420L – Engineering Electronics II Lab
Lab 1: Review of Basic RC Circuits
Shadden
Abdalla
Email address:
abdals1@unlv.nevada.edu
Below is a photo
of my webpage.
______________________________________________
LAB INSTRUCTIONS
This lab report contains:
1.
LTSpice
simulations of the circuits seen in figures 1.21, 1.22 and 1.24 using a 1uF
capacitor instead of a 1pF capacitor in the CMOS book.
2.
Each circuit
contains:
a.
The schematic
b.
Hand
calculations verifying
c.
Simulation
results verifying hand calculations
d.
Scope
waveforms verifying simulation results
e.
A discussion
of the results
3.
For the AC response
in figure 1.23 a table showing frequency, magnitude and phase
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Experiment
1: Figure 1.21
This is a basic RC circuit simulated with a peak
voltage of 1V and a frequency of 200Hz.
AC Analysis on LTSpice:
This simulation is similar to the simulation done
in figure 1.23 for which a table consisting of frequency, phase and magnitude
values is below.
FIGURE 1.23 FROM TEXTBOOK: A table for the AC response in figure 1.23 showing
frequency, magnitude and phase.
The LTspice
simulation to the right also confirms the simulation in the book.
Below are some experimental measurements of the
phase for the circuit at different frequencies to verify the AC response done
in LTSpice and in the book.
This table shows the values in figure 1.23 at varying
frequencies, phases and magnitudes. These values match the LTSpice simulation
as well as the experimental ones.
|
Frequency |
Phase |
Magnitude |
|
20Hz |
-7.252 |
992mV |
|
2kHz |
-85.62 |
74mV |
|
20kHz |
-89.5 |
7.23mV |
At 20Hz: The signal should still be oscillating.
The cursor to the left shows the values found in the LTSpice simulation for
that specific frequency. The phase measurements are almost identical in both
simulations. To the right is the photo from figure 1.23 in the textbook showing
the correspondence.
At 2kHz: The wave begins to flatten out. The
cursor on the left shows the results from the LTSpice simulation again, the
middle cursors show the experimental result and the photo on the right shows
the book simulation.
At 20kHz: The signal should flatten out enough to
be a somewhat flat line. Again the phase on the left is similar to the phase
measured in the experimental simulation and the book plot.
Transient Analysis using LTSpice and using a
breadboard. Below are snips of both circuits.
The input signal from the function generator is
the same as the input signal in the LTSpice simulation, with a frequency of
200Hz and a 1V peak to peak voltage.
Below are the simulation results in both LTSpice
and on the oscilloscope. The simulations mirror each other.
In the snip below the peak to peak voltage is
shown, which verifies the accuracy of the simulation when compared to the
LTSpice simulation.
Below are the hand calculations for Figure 1.21
confirming the simulation results from both the LTSpice simulation and the
experimental simulation.
______________________________________________
Experiment
2: Figure 1.22
This is a RC circuit where there is a capacitor in
parallel with the resistor. The impedances should be combined into one and then
the circuit can be solved using a simple voltage divider and the two
impedances.
AC Analysis
This simulation shows the different phases in
regard to unique frequencies.
Transient Analysis – The second circuit in LTSpice
and on the breadboard.
Input signal from function generator is the same
as the input signal in LTSpice, 1V peak to peak with a frequency of 200Hz.
The simulation results from our experimental
breadboard circuit match the LTSpice simulation result.
Below are the hand calculations for figure 1.22
that verify the simulation results from both the LTSpice simulation and the
experimental simulation.
______________________________________________
Experiment
3: Figure 1.24
This circuit has a different input, I used a
square wave with a specific duty cycle from the function generator instead of a
sine wave with the given frequency.
AC Analysis
This simulation shows the phase changes in regard
to different frequencies.
Transient Analysis – Circuit in LTSpice as well as
on the breadboard.
Input signal from function generator is a square
wave with a 30% duty cycle because in our LTSpice simulation, our signal is on
for 30% of the time (3m out of 10m). The input from the function generator
mirrors the input in LTSpice.
The signal generated from Vout also mirrors the
simulation we received in LTSpice.
The damping in this simulation can be fixed by
adjusting the probe used for measuring the signal.
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I backed up my files into my drive.