Download This is what the circuit looked like as I was setting it up

EE 235 Lab
Lab #4
10/4/2005
Joshua Scazzero
ID #: 558617
Introduction
This report presents an experiment is very similar to the second
experiment except that we are using two capacitors in place of two resistors,
and that we are using an alternating current (AC) source. We are basically
doing the same thing which is measuring voltages across resistors and
capacitors. We chose our own resistor values (r > 1K) and capcitors as well
as chose out own ac voltage source values (V1 and V2). We then used our
knowledge of measuring voltages to calculate the voltages across each node
in the circuit.
During this experiment I calculated the Currents of I1, I2, I3, I4 and I5
using Ohm’s law (V = I (R)) using my previously measured voltages and
resistances. I also used a lot of Kirchhoff’s Laws, in this lab report,
(Kirchhoff’s Voltage Law, KVL = ΣV = 0; Kirchhoff’s Current Law, KCL =
Σi = 0). I also used Theymn and Norton Conversions, to help me do the
hand calculations necessary to calculate the theoretical voltages and
currents.
(Note*: All experimental values were calculated using a multimeter. )
Objective
This experiment was valuable in that we could clearly see how Ohm’s
law can be applied, in order to calculate the currents in a node by finding out
the voltages and resistance of the resistors in the node. Also we can see first
hand by adding all the voltages in a loop that the total is always equal to
zero, which is in accordance with Kirchhoff’s Voltage Law.
Included in the objective was applying our knowledge of how to use a
bread board and how to create a circuit with two separate voltage sources.
Another objective of this experiment was to use caution with the sign
you give to each voltage and current measurement. Because even though the
diagram shows the current traveling in one direction if our current is
calculated as negative then it would in fact be traveling the other way! So
we should always keep in mind that current flows from positive to negative.
By doing this it will help us in verifying Kirchhoff’s laws for current and
voltage.
Materials and Equipment
Voltammeter (along with measuring wires)
DC Power Source (wires necessary to connect it.)
Several Electrical Wires
5 Resistors (greater than 1k)
Bread Board
Calculator
Pspice 9.1 Program
Methods Applied For Experiment
First thing I did is chose the resistances for each individual resistor. I wanted
to try to be consistent with the numbers on the diagram. After retrieving all 3
resistors and two different capacitors I recorded the nominal values of the resistors
and the corresponding measured values. Then my partner and I connected the
resistors onto the breadboard in a way that was electrically similar to the diagram
given. We then connected the two separate power sources to the circuit, then applied
the supply voltage using a signal generator using two alternating current sources and
an oscilloscope, to sustain the network; and then recorded the measurements, taking
special care to place the positive and negative voltages on the correct side of the
circuit.
After recording the each voltage source I proceeded to measure and record all
the following voltages: VFA, VAB, VBC, VCD, VDI, VBG, and VCH, taking care to place the
common lead of my multimeter at the last part of the wire and the other one at the
beginning part.
After measuring the voltages I calculated the following currents using Ohm’s
Law (V = R I or I = V / R): I1, I2, I3, I4, I5. After recording the currents I proceeded to
verify Kirchhoff’s laws with my obtained results. So I summed the voltages in 6
different loops of the circuit reaching the same conclusion each time and clearly
verifying Kirchhoff’s Voltage laws. I next verified Kirchhoff’s Current Law. To do
this I summed the total current entering node “b” and node “c” and again came to the
same basic conclusion and verifying Kirchhoff’s Current Law.
After this I calculated the total current by reducing the circuit using several
combinations of Norton/Theymn circuit reductions as well as Kirchhoff’s laws to find
the voltages and currents. After completing my theoretical calculations, I used the
Pspice 9.1 program to view the computer simulated calculations of the circuit. I then
printed out the information from the Pspice and related it back in tables with my other
information.
This is what the circuit looked like as I was setting it up:
See Figure 1
As you can see clearly in this picture there are three resistors and two capacitors:
See Figure 2
This is an example of a phase difference between the voltage and a resistor:
See Figure 3
This is an example of the different kinds of tools we used, including the function
generator(bottom) and the Oscilloscope (top):
See Figure 4
This is an example of superposition of a voltage across a resistor and the voltage source:
See Figure 5
This is another example of superimposing the frequency of the voltage with the voltage
source:
See Figure 6
This is the circuit I made in PSPICE 9.1:
This is the graph showing the voltages at the marker points I made:
PSPICE output list:
* Sat Nov 19 19:54:28 2005
** Analysis setup **
.ac OCT 101 10 1.00K
* From [PSPICE NETLIST] section of pspiceev.ini:
.INC "Schematic1.net"
**** INCLUDING Schematic1.net ****
* Schematics Netlist *
C_C1
C_C2
V_V2
R_R5
R_R2
R_R1
V_V1
0 B .0001104n
C D .0022n
D 0 DC 0V AC 6V
0 C 3k
B C 5k
A B 2.2k
A 0 DC 0V AC 2.9V
**** RESUMING Schematic1.cir ****
.INC "Schematic1.als"
**** INCLUDING Schematic1.als ****
* Schematics Aliases *
.ALIASES
C_C1
C1(1=0 2=B )
C_C2
C2(1=C 2=D )
V_V2
V2(+=D -=0 )
R_R5
R5(1=0 2=C )
R_R2
R2(1=B 2=C )
R_R1
R1(1=A 2=B )
V_V1
V1(+=A -=0 )
_ _(F=0)
_ _(B=B)
_ _(C=C)
_ _(D=D)
_ _(A=A)
.ENDALIASES
**** RESUMING Schematic1.cir ****
.probe
.END
**** 11/19/05 20:00:53 *********** Evaluation PSpice (Nov 1999) **************
* C:\Documents and Settings\Josh\Desktop\EE235\Lab4\Schematic1.sch
****
SMALL SIGNAL BIAS SOLUTION
TEMPERATURE = 27.000 DEG C
******************************************************************************
NODE VOLTAGE
NODE VOLTAGE
(
0.0000 (
A)
0.0000 (
B)
C)
NODE VOLTAGE
0.0000 (
D)
VOLTAGE SOURCE CURRENTS
NAME
CURRENT
V_V2
V_V1
0.000E+00
0.000E+00
TOTAL POWER DISSIPATION 0.00E+00 WATTS
JOB CONCLUDED
TOTAL JOB TIME
.08
0.0000
NODE VOLTAGE