ENGR201 Lab 2019 Fall
Lab 2, 09/12/19
Humberto Arredondo
harredondoperez@fortlewis.com

Using LTSpice For Circiut Simulation

1.- Introduction
In this lab the students were introduced to LTSpice (Linear Technology, analog electronic circuit simulator) and spice code. Also, they became to be more familiar with the lab equipment, and to make  sure that was the case, a quick quiz was given at the end of lab.

The equipment and materials used for this lab was:

• Power Supply
• Multimeter
• Breadboard
• Resistors with a different  resistance capacity.
• Wires
• LTSpice
• Spice Code

2.- Methods and Results

Task 1
Build the following circuit (Fig 1) in LTSpice using three different methods: A) Write the spice code in an external .txt file. B) Write the spice code in LTSpice but write it in the '.op' option. C) Build the circuit using electrical symbols in the library directly.

Fig 1 Circuit to be use for task 1 and 2



Fig 2. Circuit built on .txt file.



Fig 3 The circuit using '.op' option.



Fig 4 Circuit using electrical symbols





Task 2
Calculate the Current I (Fig 5) and the Voltage Vout (Fig 6)using "Ohm's Law and verify your calculation(use both simulation and on the breadboard)



Fig 5 Ohm's Law verification of current on simulation.



Fig 6 Ohm's Law verification of voltage on simulation.


Comparison of data readings on Table 1 and Fig 5 and 6.

	Calculations (Hand)	Simulations ( LTSpice)	Measurements (Breadboard)
Current I	1 mA	1 mA	1.0431 mA
Voltage Vout	2 V	2 V	1.8693 V

Table 1 Comparison of data readings


Fig 5 Data from multimeter for table 1

 
Task 3
Do a DC Sweep for V1 and Vout in LTSpice only. The DC starts from 0 V and stops at 10V.

Fig 6 Results for sumilation of DC sweep, Vin is the black line and Vout the blue line. Now our x-axis is V1.


Task 4
The power consumption of a circuit is P=V*I (Watts). What is the power consumption of the circuit in theory and in real life?


Fig 7 Power consumption of the circuit in real life is greater than in theory.


Task 5
Calculate current I and Vout of the following circuit. Verify using breadboard and simulation.


Fig 8 Circuit given for simulation



Fig 9 Calculation of Current shows that it's .909 mA.



Fig 10 Calculations of Vout show that it's -4.09 V.



Discussion

This lab helped the students to get more practice with the equipment and the used of LTSpice.