Lab 1 – EE 420L
Authored by: Daniel Senda
Email: sendad1@unlv.nevada.edu
Spring 2019
Due: 01-30-2019

1) Introduction

-Lab 1 is intended to help students refresh their knowledge of basic circuit fundamentals. The lab procedures go over basic RC circuits and common calculations that are normally done for circuit analysis.

2) Pre-Lab Description

-The pre-lab consisted of the completion of the tasks listed below by the student:
- Request a CMOSedu account from Dr. Baker in order to publish lab reports.
- Review the editing webpages tutorial.
- Read the entire lab requirements before going to class.

3) Description of Lab Procedures

-The lab required the student to simulate three circuits from the CMOS book using LTspice. Before simulating, the student had to make hand calculations. These hand calculations were then verified by the simulations. In addition, the student had to verify the simulation results with experimental measurements. This was accomplished by building the circuit on a breadboard and using the appropriate lab equipment.

→ Circuit 1

Fig 1.21 from CMOS book: LTspice circuit schematic:

Hand Calculations:
-Below are calculations for circuit 1 including magnitude, phase, and time delay of V_out.

LTspice simulation results:

As can be noted, the magnitude and time delay (6.96 – 6.24 = 0.72s) of the simulation waveform confirm the calculated values.

-The lab procedures also had the student do an AC analysis for circuit 1.
AC analysis circuit:

LTspice magnitude and phase response waveform:

-Following the LTspice simulations, circuit 1 was built and tested on a breadboard.
Circuit 1 on breadboard:

Oscilloscope waveform of circuit 1:

The oscilloscope results verified both the hand calculations and LTspice simulation for the magnitude and phase of V_out.

Experimental data for AC analysis:

Frequency	Vin	Vout	Phase
2Hz	1V	1V	0
20Hz	1V	0.98V	-8
200Hz	1V	0.62V	-51
2kHz	1V	0.1V	-87
20kHz	1V	0.05V	-89

Magnitude and phase response graphs based on data:

The frequency response of circuit 1 according to the experimental data, is close enough to the frequency response from the LTspice ac analysis.

-As the student was recording data, the student also swept the function generator in order to see the magnitude of V_out decrease as the frequency of V_in increased. Down below is the results shown on the oscilloscope.
Loop of V_in and V_out as frequency increases:

→ Circuit 2

Fig 1.22 from CMOS book: LTspice circuit schematic:

Hand Calculations:
-Below are calculations for circuit 1 including magnitude, phase, and time delay of V_out.

LTspice simulation results:

As can be noted, the magnitude and time delay (6.34 – 6.25 = 0.09ms) of the simulation waveform confirm the calculated values.

-Following the LTspice simulations, circuit 2 was built and tested on a breadboard.
Circuit 2 on breadboard:

Oscilloscope waveform of circuit 2:

The oscilloscope results verify both the hand calculations and LTspice simulation for the magnitude and phase of V_out.

→ Circuit 3

Fig 1.24 from CMOS book: LTspice circuit schematic:

Hand Calculations:
-Below are calculations for circuit 3 including RC time constant, charging time, and frequency to complete fully charging and discharging.

LTspice simulation results:

Based from the LTspice simulation waveform, it can be determined that the calculated values are correct. It takes 5ms to fully discharge and 5ms to fully discharge. This cycle can be done in a period of 10ms with a 50% duty cycle.

-Following the LTspice simulations, circuit 3 was built and tested on a breadboard.
Circuit 3 on breadboard:

Oscilloscope waveform of circuit 3:

The oscilloscope results verify both the hand calculations and LTspice simulation for charging and discharging times.

-This lab and files were backed up.

-This concludes lab 1.

Additional Links

→ Return to listing of lab reports
→ Daniel’s CMOS homepage
→ Dr. Baker’s CMOS homepage