ENGR337 Lab 2020 Spring
Lab 1
Name: Humberto Arredondo Perez
Email: harredondoperez@fortlewis.edu

1. Title:     LT Spice and edit your webside for your Lab Report

2. Introduction
In this lab we will use the method of coding (instead of schematics) to do simulations in LT Spice, using a text file and transient analysis to simulate the voltages using a few circuits given. Our goal is to generate the input and output of a signal, identifying the time delay ,to generate a DC sweep, AC sweep and DC pulse, resistor color code and recall how to edit our website for the report.

3. Materials and Methods

LT Spice	Resistors
Breadboard	KompoZer
9V AC/DC Converter  that  Provides  5V	NotePad
FileZilla	Multimeter

First, for task 1 we created a text file and wrote a code for the circuit showing in Figure 1, used transient analysis to simulate the voltages at all nodes. we built the circuit in a breadboard to check the voltages with the multimeter and we did the calculations by hand and we compared all the results in Table 1. In task 2, we wrote the code for the circuit showing on Figure 2, we displayed the signal, measured the time delay and the amplitude attenuation of the output signal compared to the input. For task 3 we did a DC sweep from -2v to 5v, the X axxis being the sweep of dV for the Vin and the Y axis being the voltage in terms of the  input(used Figure 3). In task 4, we did an AC sweep where the X and Y axis represent frequency and amplitude respectively, we did units in decades of increments, plot 100 points per decade staring from 1 Hz to 1MEG H, we used the circuit in Figure 4. And finally, in task 5, we used a DC pulse as the input voltage source to drive a Capacitor, wrote the code to implement the circuit in Figure 5 and measured the time delay.

4. Results


Table 1 comparison of calculations using the three methods

Figure 1 schematic, circuit 1 in a breadboard and hand calculations

Figure 2  Amplitude attenuation of 0.62, and a time delay of 2.26ms


Figure 3 Voltage sweep simulation done by coding


Figure 4 AC sweep simulation by coding


Figure 5 pulse on this circuit and time delay 18.5 ns


5. Discussion

In this lab we used 3 methods to calculate the voltage at different nodes of circuit 1, the results shown that all the numbers matched really well, just a minor difference on a few due to the internal resistance of the equipment used. On the tasks from 2 to 5 we just practice simulations by coding instead of schematics for practicing with LT Spice and to calculate the time delay 2.25 ms on circuit 2 and 18.5 ns in circuit 5. We went over resistor color code when building the circuit 1 in the breadboard.
This lab was a good refresher from previous classes.