Lab 1 - EE 420L
Authored
by Jacob Reed
reedj35@unlv.nevada.edu
Due: January 30, 2019
Pre-lab Work
- Your lab reports will be drafted using html and placed on CMOSedu.
- Prior to the first day of lab, but no earlier than one week before the lab starts, request a CMOSedu account, using your UNLV email address, from Dr. Baker (rjacobbaker@gmail.com).
- Review the material seen here covering editing webpages (do this before the first lab).
- Read the entire write-up seen below before coming to lab
Practice snipping an image:
Table Practice
Lab Work
For
this first lab simulate, and verify the simulation results with
experimental measurements, the circuits seen in Figs. 1.21, 1.22, and
1.24 (use a 1 uF cap in place of the 1 pF cap) of the book.
Your results should be similar to, but more complete than, the
simulation results seen on pages 17 - 23. In your report, and for
each circuit, show the
- Circuit schematic showing values and simulation parameters (snip the image from LTspice).
- Hand calculations to detail the circuit's operation.
- Simulation results using LTspice verifying hand calculations.
- Scope waverforms verifying simulation results and hand calculations.
- Comments on any differences or further potential testing that may be useful (don't just give the results, discuss them).
For
the AC response seen in Fig. 1.23 generate a table showing some
representative measurement results (frequency, magnitude, and
phase).
Show the lab TA how you are making these measurements.
If
you would like to include a plot of this measured data then using a
plotting program, such as Excel, add the image to your report.
Experiment 1: Circuit Analysis of Fig 1.21
- I
will first simulate the circuit using LTSpice, provide hand
calculations, and then show simulated and experimental measurements. I
will then provide a simulation of the bode plot for the circuit; also
adding a table showing LTSpice and oscilloscope measurements for
various frequencies.
LTSpice schematic of the circuit from Fig 1.21 Hand calculations of circuit from Fig 1.21
LTSpice waveform of the circuit in Fig 1.21
Oscilloscope measurement of the circuit in Fig 1.21
| Circuit Fig 1.21 | Magnitude (in V/V) | Phase (in °) | Time Delay (in s) |
| Hand Calculations | 0.623 | -51.5° | -715µ |
| LTSpice Simulation | 0.622 | -51.2° | -711µ |
| Oscilloscope Measurement | 0.540 | -56.2° | -768µ |
*Note: The phase difference for the LTSpice simulation was calculated
by using formula for td and algebraically manipulating to solve for phase.
Frequency Response of the circuit in Fig 1.21
| Frequency (in Hz) | LTSpice Magnitude (in dB) | LTSpice Phase (in °) | Oscilloscope Magnitude (in dB) | Oscilloscope Phase (in °) |
| 50 | -0.421 | -17.6° | -0.695 | -21.4° |
| 100 | -1.44 | -32.1° | -1.94 | -37.6° |
| 200 | -4.12 | -51.6° | -5.35 | -55.6° |
| 500 | -10.34 | -72.3° | -11.7 | -68.4° |
| 1k | -16.08 | -80.9° | -17.08 | -78.6° |
| 10k | -35.99 | -89.1° | -32.74 | -86.3° |
| 100k | -55.96 | -89.9° | -35.39 | -94.8° |
Comments: My hand calculations and LTSpice simulation results are highly correlated. There is only a 0.16% difference
between the values of magnitude for the two. However, when looking at
the oscilloscope measurement, there is approximately a 14% difference
in the magnitude between the oscilloscope and LTSpice measurements. I
think that this is due to using the "Measure" function on the
oscilloscope instead of using the cursor manually taking these
measurements. For future measurements, I will make sure be more precise by taking manual measurements. For
the frequency response, this was something difficult for me to measure
since the waveforms are wild at the higher frequencies. I feel that the
experimental results are acceptably correlated to simulation results
just because it can be difficult to take manual measurements.
Experiment 2: Circuit Analysis of Fig 1.22
- I
will first simulate the circuit
using LTSpice, provide hand calculations, and then show simulated and
experimental measurements. I will then provide a table highlighting the
differences in my measurements by: hand calculations, simulation, and
oscilliscope measurements.
LTSpice schematic of the circuit in Fig 1.22
Hand calculations of circuit from Fig 1.22
LTSpice waveform of the circuit in Fig 1.22
Oscilloscope measurement of the circuit in Fig 1.22
| Circuit Fig 1.22 | Magnitude (in V/V) | Phase (in °) | Time Delay (in s) |
| Hand Calculations | 0.694 | -6.84° | -95µ |
| LTSpice Simulation | 0.677 | -7.02° | -97.44µ |
| Oscilloscope Measurement | 0.620 | -11.0° | -140µ |
*Note: The phase difference for the LTSpice simulation was calculated
by using formula for td and algebraically manipulating to solve for phase.
Comments: My hand calculations and LTSpice simulation results are highly correlated. There is only a 2.5% difference between the values of magnitude for the two. However, when looking at the oscilloscope measurement,
there is approximately a 8.8% difference in the magnitude between the
oscilloscope and LTSpice measurements. I think that this is due to
using the "Measure" function on the oscilloscope instead of using the
cursor manually taking these measurements. For future measurements, I will make sure to be more precise by taking manual measurements.
Experiment 3: Circuit Analysis of Fig 1.24
- I
will first simulate the circuit
using LTSpice, provide hand calculations, and then show simulated and
experimental measurements. I will calculate the delay time and rise
time of the output; providing a table to show differences between my
hand calculations, simulation, and oscilloscope measurements.
LTSpice schematic of the circuit in Fig 1.22
Hand calculations of circuit from Fig 1.22
LTSpice
waveform of the circuit in Fig 1.24 showing delay
time
LTSpice waveform of the circuit in Fig 1.24 showing rise time
Oscilloscope measurement of the circuit in Fig 1.24
showing delay time and rise time.
| Circuit Fig 1.24 | td (s) | tr (s) |
| Hand Calculations | 700µ | 2.2m |
| LTSpice Simulation | 727.9µ | 2.08m |
| Oscilloscope Measurement | 755µ | 2.1m |
Comments: For
this circuit, the results for my hand calculations and LTSpice
simulation are somewhat correlated. There is a 3.9% difference between
the values for delay time and a 5.6% difference between the values for
rise time. Looking at the difference between my oscilloscope
measurements and LTSpice simulation, there is a 3.7% difference between the
values for delay time and only a 0.96% difference between the values
for rise time. Although I used the "Measure" function on the
oscilloscope and attained good results, I still should have made the
measurements manually.
Conclusion
This
was the perfect lab for me to get back into using the measuring
equipment we have, and to be able to analyze data in a meaningful way.
It also served as a great review of RC circuits and how they function.
It was great practice being able to solve for a circuit by hand,
simulating the circuit, and then measuring those same parameters in the
experiments. This lab showed me that it is very important in how
measurements are made using an oscilloscope in order to get the most
out of the equipment. In the future, I will definitely be practicing
different methods of gathering data and becoming much more accustomed
to using all of our equipment.
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