PHYSICS 3330 - Spring 2012Electronics for the Physical Sciences

✵Lecturer: Thomas Schibli

✵Lab Instructors: Minhyea Lee (Tue. 2-4:50 pm)Thomas Schibli (Thu. 2-4:50 pm)

✵Lab Coordinator: Mike ThomasonLecture 1

January 17, 2012

Course Website (check regularly!): www.colorado.edu/physics/phys3330

INSTRUCTOR CONTACT INFORMATION-See the course website : www.colorado.edu/physics/phys3330

Instructors-- Prof. Minhyea Lee (minhyea.lee@colorado.edu)

Office hours: Mon 1:00-2:30 pmOffice: Duane F-633, 303-492-1440

-- Prof. Thomas Schibli (trs@colorado.edu)Office hours: Wed 2:00-3:30 pmOffice: Duane F-527, 303-492-6125

Lab coordinator: --Mike Thomason (thomason@colorado.edu) Office: Duane G2B78, 303-492-7117

Why do I need this course?(aka. “I’m a physics major, not an engineer, and therefore, I don’t need to design electronics!” )

Alternatives:• Buy ready to use circuits /

equipment• Have someone design & build the circuits for you- Likely not perfect for your application (research means doing something nobody else has done before)- Hard or impossible to customize to improve performance

- Very time consuming (4+ weeks turn-around) (You’ll need to find someone who understands your application)- Need to send back to designer if you want make changes

Example 1: Scanning Tunneling Microscope 1986 Nobel Prize in Physics

The required circuit can be designed and built by a grad student within a week or less!

z-actuator

biasx-actuator

y-actuator

Example 2: Optical Frequency Combs 2005 Nobel Prize in Physics

The required circuits can be designed and built by a grad student within a week

SCOPE OF THE COURSE

✿ Introduction to basic building blocks for electronic circuits:

• Passive components (R, C, L):

passive Circuits (voltage dividers, & filters, etc.)

• Active components (Transistors, operational amplifiers etc.)

active circuits (amplifiers, oscillators, STMs etc.)

• Digital circuits (logic-gates, microcontrollers)

✿ Learn the characteristics of each elements and the design principles based on them.

✿ Learn how to design and analyze circuits.

Textbook and Lab Manual

● Pre-Lab problems and Lab Manual:

Please download from the course website every week.

Pre-lab problems are in the lab manuals. (You need to

complete the pre-labs before each lab!)

● Lecture Notes will be available on the course website after each lecture

● Textbook: The Electronic Companion by A.C. Fischer-Cripps

● Very useful reference:

- The Art of Electronics, 2nd Edition by Holowitz and Hill (H&H)

(Copies of H&H are available in the lab)

COURSE SCHEDULE

• Lectures: Tues/Thus 1-1:50 pm at Duane G230 - We will use Clicker and the clicker questions will be counted as 50 pts throughout the semester - For the detailed lecture schedule, see the course website.

• Labs : Tues/Thus 2-4:50 pm in DUANE G230 starting today! You must attend your assigned section. Room is accessible 24/7 with your Buff OneCard.

• Final Project: last 4 weeks of semester- project proposal due 3/22/2012 (discuss your project idea with your lab-instructor before 3/15 ! They must approve your idea!)- progress report due on 4/17 (Tue) and 4/19(Thu)- project oral presentation on 5/1/2012 (Tuesday) - written project report due on 5/3/2012

• Midterm Exam: 50 min in-class exam on March 15th (Thu)

Weekly Lab Schedule:✷Before your lab section:

(1) Read the lab manual for the upcoming lab and other required reading(2) Work through the theory on the lab with pen and paper(3) Do the pre-lab problems on your lab notebook and make a copy of it (Xerox is OK!) which you will turn in at the beginning of your lab session.

✷At the beginning of the lab: (1) Turn in your written report (3-6 pages) on last week’s experiment.(2) Turn in the photocopy of your pre-lab problem set.

✷After the lab: (1) Finish the experiment anytime except during the scheduled lab sections

and lecture time.(2) Write a lab-report to summarize your observations and measurements.

✷During the lab: (1) Do the experiment and record all data and your observations in your lab notebook.(2) Go as far as you can and analyze and make sense of the data as you take it.

For details about how to use the lab notebook and how to write the lab reports, see the Organization of Lab Notebooks and Reporting Experimental Results on the Syllabus.

LAB NOTEBOOK ✷ You will receive a lab notebook -- make sure to bring it every lab section including the final project period.

✷Number and date all pages in your book.

✷ Everything relevant to your experiment must be recorded in your lab notebook. - Record in ink; Do not erase – correct mistakes by crossing out item, leaving them legible.- Do not remove the pages from your notebook.

✷ First Page of Lab notebook should be reserved for the table of contents (lab numbers, page number, dates etc.) so that you can easily look stuff up later.

✷ When a lab instructor grades your lab notebook during the lab, he will initial and date it.

LAB REPORT(3-6 pages)Make sure to use concise and scientific language

(a)The title of experiment

(b) Objective: In one or two sentences, describe the goal of the experiment.

(c) Idea/Physics: Explain concisely the theory or calculation used in the lab

Procedure: a summary of the process you did while carrying out

experiment. Make a note of unexpected occurrences and/or special

problems and how to solve them.

(d) Data Analysis: Report the data you acquire and compare with the theory

and/or the calculated values (often you may refer to the pre-lab problems)

(e) Conclusions: Summarize your results/findings and accomplishment in a

couple of sentences. If there was anything unexpected or a big

discrepancy with the predicted value, explain it and provide enough

evidence and/or arguments why that happened. You lose points by simply

making unsubstantiated or incorrect guesses. (Don’t say “the device was

broken”. In that case, you’d have to re-do the lab before writing the report.)

Even if you work in a team, you each have to write your own lab-report!

Grading – total points 850 Clicker(50), Midterm exam(100), lab work(500), final project(200)

• Clicker questions (50 pts): there will be typically 3-5 clicker question during the lecture. You should discuss them with your peers before clicking.

• Midterm Exam (100 pts): There will be one 50-minute in-class exam given on on Thursday, March 15th, 2012. This exam will cover both, the theoretical materials covered in the lectures, and practical knowledge that you are expected to have gained from the lab work.

Grading – total points 850 Clicker(50), Midterm exam(100), lab work(500), final project(200),

(2) Lab notebook (10pt/wk) - Record the primary data and relevant observation/happening related to the experiments. - Your lab instructor will grade and initial on your lab notebook during lab section and will check on the pre-lab and the progress of the experiment. - If you miss the lab, you will not get any Lab notebook points.

(3) Lab Reports (30pt/wk) - Write 3-6 pages (including figures. Do not exceed 10 pages!) of a brief and clear account of what was observed during the experiments and the

conclusions from them. - Due at the beginning of each lab section. - Late penalty: 25% off if 1 hour to 1 day late, 50% off if 1 day to 1 week date. No lab report will be accepted more than 1 week late!

Lab work (50 pts for each lab, total 500 pts) : We have 10 labs and for each lab the following will be graded.

(1) Pre-Lab Problems (10pts/wk) : They are in the lab manual - Due on the beginning of each lab section - Late submission will NOT be accepted. - Do your pre-lab problems on your lab notebook and turn in a separate copy

for grading to your lab instructor

Grading – total points 850 Clicker(50), Midterm exam(100), lab work(500), final project(200)

•Final Project (200 points) :

(1) Written project proposal (25 pts)- due on March 22nd 4pm - In 1 to 2 pages of write-up to explain main idea and approach of project.

- must talk to your lab instructor to get pre-approval of the ideas by March 15th.

(2) Progress Report (25pts)-- due at the beginning of the lab on week of April 17th. - 1-3 pages describing your progress so far.

- Include the (almost) complete circuit diagrams for your project.

(3) Oral Presentation (75pts) – on May 1, 2012, 9 am – 4pm (pick a slot!) - plan to use a computer-based presentation (e.g. PowerPoint etc).- Quality and substance of presentation will be the subject of evaluation

- Demonstration of your project also should be the part of the presentation.

(4) Final Project Report (75 pts) - due on May 4th , 2012 4 pm. - submit fully polished, typed documents with complete figures, diagrams

and data. - only one report per group IF you work in team of two. You must specify the contributions of each member (such as ideas, circuit design, write-up, etc.) as part of

the write-up.

Other things to keep in mind:

✔ Lab Access by Buff One card : Your Buff one card will open the door 24/7

if you are registered for this course. The Lab door should be closed all the

time. Don’t prop the door!

✔ If you are the last to leave the lab, first be sure to turn off all equipment, especially soldering irons and hot plates. Then close all windows and turn off the lights.

✔ Never prop the door open. Alarm will sound after some time. The equipment is expensive and it would be very hard to replace.

✔ Report any faults or damage that occur to any instrument or non-trivial component an instructor or to Michael Thomason as soon as possible.

J-LAB SAFETY – (abbreviated) ✔ Be aware of the electrical dangers! – See the ‘Lab Safety’ pdf on

the course webpage

✔ Never work with any hazard that you do not understand.

✔ Never work in a laboratory alone. This can sometimes be a very

frustrating constraint but it’s important.

✔ Always wear eye protection when using power tools or handling

chemicals.

✔ Keep your work area neat and uncluttered.

✔ Keep all electrical cables off of floors and away from traffic.

✔ Know where fire extinguishers and exits are located.

✔ Never bring food or drinks into a laboratory.

✔ In case of any emergency, call 911, and notify an instructor if

possible.

A2Who is responsible for your safety?

A: The US Government

B: The State of Colorado

C: The University of Colorado

D: The Physics Department

E: Yourself

A3

What is the most likely way a physicist will die at work?

A: Toxic chemicals

B: Explosions

C: Electrocution

D: Disgruntled graduate student

E: Pizza overdose

F: Old age

A4What one of the below can kill you?

A: Current

B: Voltage

C: Power

D: Capacitance

E: Resistance

EFFECTS OF CURRENT (AC and DC)

• 10 to 20 mA painful sensation• 20 to 40 mA muscular paralysis, cannot let go• 40 to 80 mA breathing is difficult• 100 to 200 mA fibrillation of the heart and death• > 200 mA heart muscles are clamped.

• Recovery is possible with immediate first aid. • Be sure the power is off before touching a helpless person!!! 

A6

Is 15 V safe if you have dry hands?A: YesB: No

•10 -100 mA can kill you!

•You will generally work with 15 V max.• Internal resistance ~ 500 W• Skin resistance ~100k W

This week’s labThe work-bench equipment

Oscilloscope

to ‘see’ what your circuit

does

Power supply

to power your circuits

Function generatorto ‘feed’ your circuit with a time-varying

signal

Breadboard…where your circuits will

live.

Multimeterto measure

voltage, current, and resistance.

Oscilloscope

to ‘see’ what your circuit

does

Power supply

to power your circuits

Function generatorto ‘feed’ your circuit with a time-varying

signal

Breadboard…where your circuits will

live.

Multimeterto measure

voltage, current, and resistance.

Think of these as tools to “see” what’s going on in your circuit.

Think of them as these gauges, which allow you to safely fly a plane at night!

So if you can fly an airplane with a handful of rusty steam gauges, you

should be able to figure out what your circuit does with some fancy scopes!

But both do require practice!

Aliasing on digital oscilloscopes

Red = real signalBlue = scope display

Black points = sampling times

Things you need to know about complex numbers for Phys3330

1.Perform algebraic operations on complex numbers and represent a given complex number graphically and express it in polar form.

2. Represent a sinusoidal function as the real and imaginary part of an exponential and use this representation for adding trigonometric functions.

3. Set up a linear differential equation to describe the behavior of LCR circuit that is subject to an applied sinusoidal voltage.

4. Use complex exponentials to solve homogenous and inhomogeneous linear differential equations with constant coefficients.

1. Complex number - The imaginary unit: 

(a)General complex number  (where x and y are REAL number)

real part of z,  x= Re z imaginary  part of z,  y= Im z

       

       

(c) Complex conjugate (z → z*) :  Replace i  with -i

and

→ the modulus of z 

→✱

✱

✱

✱

(b) Arithmetic with complex numbers z1,2: 

+−×

(used in rationalize the denominator)

÷

2. Power Series for exponential and trigonometric functions:

Now compare trigonometric and hyperbolic function in complex number:

Euler’s Formula

3. Polar representation of a complex number z=x+iy

y (imaginary)

x (real)

z=x+iy

rϕ

Representing  z=x+iy by the point (x,y)

Then,

where, 

So we can always write  x y

✵Polar representation is advantageous for multiplication and division!

Let

then 

Homework Problems

1.  Let

(a) Represent z1 and z2 in the complex plane and find their real and imaginary part

(a) Evaluate z1 + z2 and

2. By writing out cos θ in terms of exponentials and using the binomial expansion, express (cos θ)5 in terms of cos θ, cos 3θ and cos 5θ.

3. Evaluate the sum

4. Suppose that frequencies        and       differ only slightly. Use the complex exponential,express the sum                                             (A is a constant)   in the form of 

where  A(t) is a slowly varying function of time.

3. Polar representation of a complex number z=x+iy

y (imaginary)

x (real)

z=x+iy

rϕ

Representing  z=x+iy by the point (x,y)

Then,

where, 

Now we can always write  x y

✵Polar representation is advantageous for multiplication and division!

Let

then 

✵Example. Find z  satisfying z3 = -8i

(solution) Since  they all have modulus 2. Thus

Now,

thus, and,

So,