215 Materials and Devices
LAB 3: Circuit
In this exercise students
will use circuit simulation to perform circuit analysis. Circuit simulation
plays a major role in circuit design, and, as such, there are many circuit
analysis software systems to choose from.
For this lab, the students are free to use any circuit simulation
software at their disposal. The onsite
lab provides the students with access to National Instruments Multisim circuit
simulator. Students can also download
and use a popular free circuit simulator named LTSpice (.linear.com/designtools/software/">http://www.linear.com/designtools/software/). LTSpice is available for both Windows and Mac
OS X.With the software, circuit designers can quickly design, simulate, and
test circuits.To develop skills in circuit simulation, the students will
construct and simulate a circuit to determine the electrical propertiesand
characteristics of the circuit elements.
EQUIPMENT:National Instruments Multisim, LTSpice, or
Comparable Circuit Simulator
Part I: Resistive Circuit Network
Many times circuit
designsconsist of complex circuit schematics that may contain hundreds of
circuit elements. The knowledge of the voltage and current results for these
elements must be determined. Conventional hand analysis is impractical for
these types of circuits, so the electrical properties of the elements must be
determined using simulation software.
In the circuit diagram
shown below, the student is to capture the circuit using your circuit simulator
and perform a linear DC sweep analysis from 1 to 10 volts at 0.5 increments.
The DC sweep analysis is performed by using the DC dot command.
By clicking on the node
for each element, the simulation shows the voltage sweep across that
element. Clicking on the element itself
shows the current going through the element.
Using the results of this simulation analysis, fill in the table below.
(a) Using the DC sweep analysis results from your
circuit simulation, fill in the table below.
Voltage Source V
Volts on 15W
Volts on 5W
Volts on 10W
(b) In the simulation, click on the 10 V voltage
source, the 12.5W, the 10W, and the 30Wresistor to show the current going though each
element. At 10 V, add together the
current going through each element. What
is the sum of these currents?
Part II: Resistive Circuit Network Comparison
(a) Using the above circuit diagram, change the
10 V voltage source on your schematic to a sine wave function. Give the sine wave a DC offset of 0, an
amplitude of 10, and a frequency of 1000 Hz.
(b) Change the DC sweep analysis to a Transient
analysis. Set the Stop Time to 20m
(c) Run the simulation. Click on the node above the voltage source to
get the voltage across the source, and then click directly on the 30W resistor to get the current across this
(d) Capture this diagram and put it in your
(e) Next, cut the 30W resistor from the schematic and replace it with a 10u
Farad capacitor. Repeat the above steps
used on the 30W resistor.
(f) Next cut the capacitor from the schematic and
replace it with a 10m Henry inductor.
Repeat the above steps.
(g) In your report, describe and compare the
waveform results in the diagrams for the 30W resistor, 10u Farad capacitor, and the 10m Henry