EE101: Introduction to Electrical Fundamentals Lab

EE101 Final Exam
Review topics document (12/4/2003).
The final exam will be given during normal class time.  Like the midterm, the final exam will consist of a multiple-choice section and a practical section.  The multiple choice problems (about 20) will cover material from the 11 lab exercises, the reading assignments, and topics discussed during the lab sessions.  The practical problems will require observing a circuit and test equipment set up at a lab station, then answering questions such as waveform period, frequency, and peak-to-peak voltage displayed on the oscilloscope, the current in a circuit branch based on the measured voltage and the known resistance, and so forth.

The exam is closed book (no books or notes).  Calculators are allowed for numerical computation only (no stored formulas, text, or other material).  Students will work individually, not as teams.

NOTE:  Instructions on viewing the list of final exam scores and course grades will be emailed to the address of each student.  To verify your official email address, go to MSU My Info.

Lab #11:  Digital Logic
This is the last lab of the semester!  In this exercise you will use some simple digital logic gates to make a combinational logic network.  NOTE that you need to look up a datasheet and prepare some information PRIOR to coming to the lab.

You will fill out the course/instructor evaluation form and outcomes assessment questionnaire this week.  Please give your honest and detailed assessment of the course, the instructor, and areas that should be addressed in the future.  Thank you!

Reminder:  the course final exam will be held in class on December 11.

Here is a final exam review document (handed out in class on 12/4/2003).

Thanksgiving holiday -- no lab for sections 3, 4, and 5 this week
 

Lab #10:  Voice-activated switch kit: completion and testing
You are all doing a very good job with the kit assembly!  Keep up the concentration and good work.

REMEMBER, the entire assembly of the kit (except for C3 and mic) needs to be done BEFORE you arrive at class this week.  See me or ask the department secretary if you would like to get into the lab to finish up your soldering.

ALSO, if you have not done so already, you should perform the op amp measurements from Lab #9. After that, proceed with the final assembly and testing of the entire circuit.  Plan to turn in the completed Lab #10 write-up (and Lab #9 if you did that after the last lab session) before you leave on Nov. 20.

Reminder:  we will work on Lab #11 (digital logic) on December 4, then have the course final exam in class on December 11.  Yep, you're almost done with EE101!

Lab #9:  Voice-activated switch kit: assembly
This week and next week are devoted to constructing the voice activated switch (VOX) kit.  Each student (not each group) must build his or her own kit.  Students who have paid the College of Engineering Program Fee will receive the VOX kits during the lab session.  Students from other colleges will need to buy their kits in advance (about $10) from the ECE Stock Room (622 Cobleigh Hall). 

Note that you should NOT install capacitor C3 nor the microphone onto the board until you do the required tests on the op amp stages:  be sure to read and understand the lab procedures BEFORE you start assembling everything.

I recommend that you solder some spare wires onto the PC board connections (A-F) so that it will be easier to hook up the input and output circuits from your breadboard to your PC board.  You can attach the studs in the kit later if you want.

The physical assembly of the kit (except for C3 and mic) needs to be done BEFORE you arrive at class November 20.  If you do not finish the assembly during the lab period this week on November 13, be sure to come back sometime before the following week and get the soldering done.

Lab #8:  2-stage Amplifier

This experiment is a continuation of Lab #7, but this time with a two op amp circuit.  The circuit is similar to what will be used in the voice activated switch project (Labs 9 and 10).

NOTE that you will begin assembling your voice activated switch (VOX) kit next week.

You will be soldering components to a printed circuit board.  If you haven't ever done this sort of thing, refer to a Soldering Tips document, and the circuit assembly notes previously handed out in class.

Lab #7:  Op Amps

NOTE:  You will need to do P1-P4 of Lab #7 BEFORE you come to class!  It requires looking up some information on the web (an LM358 datasheet).

HOMEWORK:  Please read the textbook pp. 238-242 before coming to lab this week.

Topics:  Reading a datasheet for an integrated circuit, understanding basic op amp features, and assembling simple op amp circuits on the breadboard.

Midterm exam results summary (sections 3, 4, and 5): 

MIDTERM EXAM

The exam is CLOSED BOOK and CLOSED NOTES.
BE SURE TO BRING YOUR CALCULATOR.

The exam will be held during the normal lab time.  The exam will consist of a multiple-choice section and a practical section.  The multiple choice problems (about 20) will cover material from Lab #1 - #6, homework, the reading assignments, and topics discussed during the lab sessions.  The practical problems will require observing a circuit and test equipment set up at a lab station, then answering questions such as the frequency and peak-to-peak voltage displayed on the oscilloscope, the current in a circuit branch based on the measured voltage and the known resistance, and so forth.

The exam is closed book (no books or notes).  Calculators are allowed for numerical computation only (no stored formulas, text, or other material).  Students will work individually on the exam, not as teams.

Exam review suggestions. 

Key areas to review are:

• Basic lab procedures (using the oscilloscope and understanding scope measurements; using the multimeter for current, voltage, and resistance; breadboard connections, etc.)

• Ohms Law, Kirchhoffs Laws and HOW TO APPLY THEM!

• Electrical measurement units, unit prefixes, and conversions

• Resistor and capacitor schematic symbols and device labels (formula)

• Diodes

• Series and parallel resistor combinations AND formulas

• Component tolerance (nominal vs. actual)

• Graph and report preparation

• MATLAB basics

Lab #6:  Introduction to Matlab

We will meet in the ECE Computer Lab (Room 625 Cobleigh) this week.  You need to have an MSU computer account AND an ECE printing account BEFORE you arrive at the lab!

Topics:  Using MATLAB for simple calculations, plotting, and signal generation.

Reminder:  The mid-term exam will be held during the regular lab session time on Thursday, October 23.  Exam topics will include everything up through October 16 (labs, reading assignments, and homework).

Lab #5:  Electric shock, and a simple diode circuit.

Topics:  Resistance of the human body to electrical current; diode half-wave rectifier circuit.

Reminder 1: Career Fair reports are due at the START of the lab session on Thursday, October 9.

Reminder 2: Next week (October 16) we will meet in Room 625 to do a computer lab assignment.  Be sure to have your computer account active and ready to print!

Reminder 3:  The mid-term exam will be held during the regular lab session time on Thursday, October 23.

Lab #4:  Frequency, Period, and Phase.

Here is an oscilloscope worksheet, and here is the worksheet solution.

Reminder: Remember the Career Fair on Friday, October 3.  Your assignment is to write a report after interviewing one of the recruiters.  This report is due at the start of the lab session on Thursday, October 9.

Topics:  Frequency, phase, and voltage/current relationships.

• Frequency of a periodic waveform is measured in hertz [Hz], meaning cycles per second.  The period of a periodic waveform is the reciprocal of the frequency, with the unit of seconds.  The period of a waveform can be determined directly from the oscilloscope screen by counting the number of divisions between waveform repetitions, then multiplying by the time scale:  Y divisions times X seconds/division = period.  The frequency can then be determined as the reciprocal of the period.

• Measuring time differences on the oscilloscope is often more accurate if "steep" waveform segments are compared (like zero-crossings of a sine wave) rather than "shallow" features (like the rounded peaks of a sine wave):  it is easier to locate the steep feature at a specific time.  If zero-crossings are used, be sure the waveform is centered properly so that the centerline is actually at zero.

• Two signals with the same frequency may have a relative time delay between them.  This is called a phase shift.  If the two waveforms are displayed simultaneously on the two separate channels of the oscilloscope, the delayed waveform will appear shifted to the right relative to the undelayed waveform.  The 'scope can be used to measure the relative time delay, and the phase shift can be calculated by determining the fraction of the waveform period that is represented by the delay:  phase shift = (delay/period)*360 degrees, for example.

• When two signals with a phase shift are added together, the amplitude of the sum will not in general be equal to the sum of the individual amplitudes, since the peaks of the waveforms do not occur at the same time.  The MATH function on the 'scope allows the sum (or difference) of the two input channels to be displayed on the 'scope screen.

Lab #3:  Capacitors and Frequency Response.

Assignment 1: Make plans to attend the Career Fair on Friday, October 3.  Your assignment is to write a report after interviewing one of the recruiters.  This report is due at the start of the lab session on Thursday, October 9.

Assignment 2:  Are you starting to wonder why clearly specifying measurement units is so important, and why the instructor is so picky about it?  Read the article from the December 1999 issue of IEEE Spectrum magazine on why the Mars Climate Observer crashed into Mars rather than going into the intended orbit:  Why the Mars Probe Went Off Course.  One short excerpt:

"NASA assigned three separate teams to investigate the embarrassing, US $125 million debacle and determine its cause. Preliminary public statements faulted a slip-up between the probe's builders and its operators, a failure to convert the English units of measurement used in construction into the metric units used for operation."

Topics:  RC circuits, frequency response measurement, semi-log graphs.  Here is the theoretical frequency response plot for the RC and RR circuits in Lab #3.

• Capacitors are circuit elements that temporarily store electrical charge.  If a circuit causes a current to flow through a capacitor, a voltage develops across the capacitor that is proportional to the amount of electrical charge delivered by the current.  The unit of capacitance is the farad, abbreviated "F".

• Physical capacitors come in a variety of shapes and sizes.  Plastic and metal film capacitors look a little bit like tan, brown, blue, or red Chiclet-brand gum with two parallel wires coming out.  Aluminum electrolytic capacitors look like metal cans about the diameter of a pen cap.  Some capacitors require a specific polarity (positive/negative) in the circuit.  Typical capacitors used in ordinary circuits range from hundreds of picofarads (pF, pico = 10^-12) to thousands of microfarads (mF, micro=10^-6).  For some reason, capacitors are almost never referred to in nanofarads:  it is traditional to say 0.001mF or 1000pF instead of 1 nF.

• Capacitors are often labeled with a 3 digit code followed by a letter, like "103K".  Referring to the three digits as ABD, the capacitor value in picofarads is ABx10^D pF.  For example, "103" would mean 10 x 10³ pF, or 0.01mF (microfarads).  The letter indicates the tolerance:  M=20%, K=10%, J=5%, G=2%, F=1%, and E=0.5%.

• Simple circuits involving resistors and capacitors are called "RC circuits".  RC circuits often allow the capacitor to charge or discharge through a resistor, and the larger the resistance the longer it takes for the capacitor to charge or discharge.  The product of R and C is known as the RC time constant for the circuit, and the units of R (ohms) times C (farads) is seconds.  The reciprocal of the time constant is 1/RC, and has the units of radian frequency (radians per second).  Radian frequency can be converted to hertz (cycles per second) by dividing rad/sec by 2p.  This frequency roughly corresponds to the separation between the low frequency behavior of the circuit and the high frequency behavior of the circuit.

• For this experiment you will be producing a graph of the frequency response of a simple RC circuit.  The graph will be on semi-log graph paper.  This type of graph paper has one axis scale that is linear (normal) and the other axis scale is logarithmic in powers of 10.  This type of graph is useful when there is a known exponential relationship for the data, or if there is a large range of values (small to large) to be plotted.

Lab #2:  Voltage and Current in simple circuits.
 

Assignment:  before next week (Lab #3), read chapter 20 up through page 154.  Also read chapter 31, pp. 279-287.

Topics:  Kirchhoff's Laws, voltage and current measurement.

• A circuit node is a point where two or more elements (circuit branches) are connected together.  A circuit loop is a closed path from one node through a sequence of circuit branches and back to the starting node without the path crossing itself.

• Kirchhoff's Current Law (KCL) states that the sum of all currents entering a node must be zero.  In other words, the total current entering a node must equal the total current leaving the node.

• Kirchhoff's Voltage Law (KVL) states that the sum of voltages around a circuit loop must be zero.

• The convention for voltage and current in a resistor is

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Carefully follow Multimeter procedures in order to keep track of signal polarity.

• For current (ammeter mode), connect the red lead to the meter's current input and the black lead to the common input.  The meter must be inserted into the circuit branch where the current is to be measured:  current must flow through the meter.  If the current reads positive, this means the current is entering the red lead, passing through the meter and exiting the black lead.  If the current reads negative, the flow enters the black lead and exits the red lead.  The ammeter acts like a short circuit (no voltage across the meter).

• For voltage (voltmeter mode), connect the red lead to the meter's voltage input and the black lead to the common input.  The meter must be used in parallel with the circuit branch between the nodes where the voltage is to be measured.  If the meter indicates positive voltage, the red lead is at a higher potential relative to the black lead, and vice versa.  The voltmeter acts like an open circuit (no current through the meter).

Lab #1:  Series and Parallel resistor combinations, simple circuits, and resistor tolerance specs.

Reminder:  I will collect your table of SI units at the start of class!
Assignment for this coming week:  Review Lab #2, and the multimeter notes.

Topics:  Ohm's Law, series and parallel resistor combinations.

• Ohm's Law:  V= I R
  V is voltage with the unit volts, I is current with the unit amperes, or just amps. The unit of resistance is volts/amps, which is called ohms.
  The voltage across a resistor is linearly related to the current through the resistor.  If we make a graph with measured voltage on the vertical axis and measured current on the horizontal axis, the data should produce a line with slope equal to R.  You can think of the resistor as taking a current and "making" a voltage equal to I times R.

•  Resistors connected in series are connected end-to-end.  The total equivalent resistance for resistors in series is simply the sum of the individual resistances.

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• Resistors connected in parallel are all connected between the same pair of nodes.  The total equivalent resistance for resistors in parallel is the reciprocal of the sum of the reciprocals of the individual resistances.

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• More complicated networks of resistors can be simplified by applying the parallel and series formulas over and over on each branch of the network.

• Resistors have a nominal value indicated by the colored bands or other labeling.  The actual (measured) resistance will vary from the nominal value due to subtle mechanical and chemical differences that occur during manufacturing.  The manufacturer specifies the maximum deviation from the nominal value as a percentage.  This range of deviation is called the tolerance of the resistor family.  Typical tolerance values are 1%, 5%, or 10%.

First class meeting

We will go over the course syllabus, fill out a survey, receive lab kits, and do a quick introductory lab exercise.

Assignment: 

1. Students who have paid the College of Engineering Program Fee will receive component kits during the lab session.  Students from other colleges will need to buy their components (about $3) from the ECE Stock Room (622 Cobleigh Hall).  All students will need to obtain a prototype "bread board" (about $24) from the ECE Stock Room, or you can buy or borrow a bread board from some other source.
   
   There will also be a separate project kit to obtain later in the semester.
    

2. Read chapters 1, 5, and 19 in the textbook.  NOTE in particular the details of series and parallel resistor combinations (pp. 123-125).

3. Review the first lab experiment.  Lab #1:  Series and parallel resistance combinations.

4. Prepare a table showing the standard SI unit prefixes for the range from 10^-12 to 10¹².  Hand in at the start of class next week (September 11).  Your table should look like:

Multiplier        Unit Name       Abbreviation
  10^-12              pico                     p
  10^-9                nano                    n
...etc...

Topics:  Basics of oscilloscope and function generator.

• In ECE we use lots of range units:  pico (10^-12), nano (10^-9), micro (10^-6), milli (10^-3), kilo (10³), etc.

•  Oscilloscope shows voltage (vertical scale) vs. time (horizontal scale).  The scope display shows the time resolution and amplitude resolution in units per division, where a "division" refers to the approximately 1cm square grid lines on the screen.

• We generally will set the scopes for 20MHz bandwidth:  go to the vertical display menu (button below vertical controls) and select 20MHz.

• If the waveform "rolls" horizontally instead of sitting still, make sure the trigger level and channel is selected properly.

• Adjusting the vertical and horizontal controls acts sort of like a microscope for electrical signals:  we can see details on very short time intervals. 

• Relationship between frequency (Hertz, cycles per second) and period (seconds per cycle) is a reciprocal:  period = 1/frequency.