Physics 116A, Fall, 2009

Lab: Sec. 1 - M 3:10-6:00 PM in Rm. 152 Roessler
Sec. 2 - W 3:10-6:00 PM in Rm. 152 Roessler

Instructor: Prof. David E. Pellett, 337 Physics, (530) 752-1783,

Office hours for Week 8 (also posted in SmartSite announcements and schedule):

• Tuesday, Nov. 17, 2:10 - 3 PM in 116 lab (152 Roessler)
• Thursday, Nov. 19, 4:10-5 PM in 116 lab (152 Roessler)

E-mail: pellett at physics dot ucdavis dot edu (modify the format to use).

TA: Evan Friis, 327 Physics

Office hour: Thursdays, 2-3 PM in 327 Physics

E-mail: friis at physics dot ucdavis dot edu (modify the format to use).

Physics 116A is an introduction to analog electronics. It is valuable for students who want to do experimental work, who want to understand the basis of our omnipresent electronic technology or who want to develop new instrumentation or technology. The course is a prerequisite for Physics 116B, which covers digital electronics and computer fundamentals.

Text: Bobrow, Fundamentals of Electrical Engineering, 2nd ed.

Scope: Analog electronics in Ch. 1-10 and Ch. 16 of text by Bobrow, concentrating on circuit response to sinusoidal signals. Includes brief introduction to semiconductor devices and linearized models for their performance.

Lab manual: see links in the chart below. Please download and print a copy before the lab each week to bring to lab. (Note: instructions may be edited/updated during the week prior to the lab).

Lab notebook and reports: You will need to keep a clear record of your work in the lab along with the data which you collect. Traditionally, this is done in a bound logbook, although there is a trend toward on-line electronic logbooks for some experiments. For these labs, you will use an 8.5” x 11” loose-leaf notebook of your choice (be sure to bring it to the first lab). This way you can turn in your notes from a given experiment as part of the lab report without losing access to the rest of the logbook. We encourage you to use quadrille-ruled paper (such as the Engineer's Composition Pad available in the bookstore). This simplifies making tables, quick graphs and diagrams. Note that it is best to use only one side of the page with this paper. Each student must keep his/her own logbook, although data sheets can be shared between lab partners via photocopies.

• The Lab Syllabus (last year's version for now) has more information on lab policies and procedures.
  

Course Grading Percentages: 9% Quiz 1, 18% Midterm Exam, 9% Quiz 2, 25% Lab (required, on time), 10% Homework, 29% Final Exam.

Web Sites: Log onto SmartSite and choose PHY 116A A01-A02 FQ2009.
There you will find various resources (such as homework and exam solutions) and a link to the present page on the Physics Department site:
http://www.physics.ucdavis.edu/Classes/Physics116/Physics116.html

Lecture Presentation pdf Files: For some lectures, presentations were prepared and projected from my laptop computer. They are linked as pdf files in the chart below in one of the columns labeled "| M | W | F |" with a link shown as "P04" for "Presentation 2004." Beware: these may not be up to date for this year. They may be updated (or new presentations added) following the lecture. If so, the label will be "P09."

Here are general reading assignments from last year. They are preliminary. Some variations can be expected since the lab schedule has been modified to fit in with the Veterans' Day holiday on Wednesday, Nov. 11. Problem assignments will be added as we go along.

• The assignments are keyed to the week number in the first column of the table above.

Assignment 1 (Week 2):

• Read Bobrow, Ch. 1, Ch. 2; Problems due in class Monday, 10/5/09: Ch. 1: 1.7, 1.17(a) [note v_s=v in figure and the use of conductance values (upside down omega = mho = Siemens = 1/Ohm)], 1.18(a), 1.21, 1.23(a), 1.35, 1.42(b), 1.53(a,b).

Assignment 2 (Week 3):

Read over Ch.3 for important points: this introduces the capacitor and inductor as linear circuit elements (very important) and the Op Amp differentiator and integrator discussed in class and Lab 2. There is also a review of ODE's (ordinary differential equations) with constant coefficients and damped oscillations in LRC circuits. I say "review" since ODE's are covered in the Math 22 series. Read it over to see the connection between ODE's and circuits. Physics 116A will be concerned mainly with steady state AC circuit response (i.e., for sinusoidal inputs), although we will discuss the natural response of a circuit again in Sec. 5.3 (on complex frequency, s). We will return to the step function and pulse responses of circuits in detail in Physics 116B.

Read 4.1-4.5 to understand the use of complex V, I and impedance, Z, to find the steady state AC response of a circuit. This also includes AC power and rms values of V and I.

Learn how to use phasors and review operations with complex numbers so you can find amplitude and phase relations in AC circuits using the principles from Ch. 1 and 2 as applied to AC circuits (including Thevenin equivalent).

Read 5.1 on frequency response of an RC circuit (needed for Lab 3).

• Problems (still on DC circuits) due in class Monday, 10/12/09: Ch. 1: 1.57; Ch. 2: 2.7, 2.11, 2.20, 2.27, 2.30, 2.37, 2.39, 2.57.
  • Examples worked in class Friday, Oct. 9, 2009 (using (a) mesh currents and (b) Thevenin equivalent circuit)
  • Example: Thevenin equivalent of DC circuit with dependent source

Assignment 3 (Week 4):

• Read 5.2-5.4:
  • resonance
  • complex frequency, s
  • linear systems with feedback
    (We'll return to feedback near the end of 116A)
• Problems due in class Wednesday, 10/21/09: Ch. 3: 3.1 (v= v_L), 3.7, 3.15(b,d); Ch. 4: 4.7, 4.10, 4.12, 4.15, 4.18, 4.28(c).

Assignment 4 (Week 5):

• Read Ch. 6 on semiconductors and diodes, excluding pp. 377-81 (on diode logic circuits, left for 116B)
  • Semiconductor fundamentals and diodes will be introduced starting this week.
  • For the Lab: The lab this week gives a "hands-on" introduction to the silicon diode characteristic I–V curve and the use of a diode as a rectifier of AC signals. Read the lab writeup before coming to lab. In the text, the characteristic curve is described in Sec. 6.3. Diode rectifiers are discussed in the beginning of Sec. 6.4. Zener diodes are covered in Sec. 6.6.
• Problems due in class Wednesday, 10/28/09: Ch. 4: 4.42; Ch. 5: 5.1, 5.3,5.15(a), 5.22, 5.32, 5.39(a,b,c,d), 5.46(a).
  • Note on Prob. 5.22: Find the resonance frequency using the criterion (for a circuit with at least one capacitor and one inductor) that the imaginary part of the admittance (or impedance) equals zero at resonance. Details in text, p. 276.
• A Note on complex frequency, s:
  • For the following discussion, see if your browser can reproduce Greek characters. This should look like the lower case Greek character, omega: ω. And this should look like a lower case sigma: σ. If another character/font appears, you may have to try to recognize it for what it is supposed to represent.
  • Complex frequency, s=σ+jω, is explained in Sec. 5.3 and example 5.6 of the text. The response of a linear circuit driven by the waveform V_in=V_sexp(st) can be found exactly as was done before for complex sinusoids (V_in=V_sexp(jωt)). Resulting expressions will then have s substituted for jω wherever jω appeared in the sinusoid case. The impedance of an inductor would be Z=sL instead of jωL. For a capacitor, Z=1/(sC). You can do circuit analysis for complex s as was done before with jω but using these impedance relations in terms of s rather than jω.
  • Note that the usual sinusoidal expressions are obtained if we let σ=0 (s=jω, on the imaginary axis in the complex frequency plane). For nonzero σ, we have functions which are sinusoids multiplied by exp(σt). Such sinusoids decay exponentially for σ<0 (s in left half of complex frequency plane) or grow exponentially for σ>0 (s in right half of complex frequency plane).
  • This is useful for characterizing transfer functions H(s) in terms of the locations of their poles and zeros in the complex frequency plane.
  • Illustration: Here is a web page that allows you to place two complex-conjugate poles and two complex-conjugate zeros in the s plane and plot the magnitude and phase of H(s).
  • Here are notes on H(s) and active filters as shown in class (also linked in Outline, above for Monday, Oct. 26).

Assignment 5 (Week 6)

• Problems due in class Monday, 11/9/09: Ch. 6: 6.2, 6.5, 6.8, 6.16, 6.19, 6.22(a), 6.40, 6.44, 6.64(a).
• Read 7.1-7.3, 9.1 (BJT basics and BJT amplifiers) - needed for the lab (no lab Nov. 2 - meets Nov. 4 and Nov. 9; Nov. 11 is a holiday). Also read the lab writeup before coming to lab.
  • For BJT transistor amplifiers - common collector (or emitter follower), common emitter, common base - covered in Chapter 9,
    • learn how to determine the operating point ("Q point") of a transistor amplifier (BJT biasing);
    • learn about the simple Ebers-Moll and small signal BJT models;
    • learn how to derive the circuit for the small signal AC model of an amplifier from the actual amplifier circuit using an appropriate small signal BJT model;
    • learn how to use the small signal model to derive the amplifier voltage gain, input impedance, output impedance, etc.

Assignment 6 (Week 7):

• Problems on BJTs (and one on diodes) due Wednesday, 11/18/09: 7.3(c), 7.10, 9.3, 9.12, 9.15(b), 9.19 plus this problem.
• Read 16.1-16.3 and the Lab 4 writeup on SPICE (for SPICE exercise from Lab 4). Note: SPICE does not have the .PROBE command - this is a feature of PSPICE. See the section on SPICE in the Lab 4 writeup for some information on how to do plots.
  • Some changes are needed for the writeup on Spice usage on the computers in Room 106.
    • The program is now called ngspice, so the line near the center of Page 4 should read "ngspice LRC.cir" instead of "spice3."
    • Remove the phrase "ydel 20" in the plot command (causes problems with plot positioning when rescaling multiple plots).
    • Also, to work remotely, you need to connect to one of the Room 106 computers, not "lifshitz" (or "student").
  • To keep things simple, I recommend that you do this assignment using the Room 106 computers and ngspice. But I encourage you to get a version of SPICE to work on your personal computer (see links below, updated recently).
    • MacSpice works well on Macs and is integrated with the free Textwrangler text editor. (Latest version defaults to angles in degrees.)
    • If you have a Windows machine, WinSPICE should be adequate for this class.
    • LTSpiceIV is a more full-featured version of SPICE for Windows with a GUI and the ability to work with circuit schematics. This has also been made to run on the Room 106 computers using the Wine program.

Assignment 7 (Week 8):

• Read 8.1, 8.2, 9.2 (FET basics and FET amplifiers) - needed for the lab - also read the lab writeup before coming to lab;
• Quiz Friday, Nov. 21 over material covered from Ch. 6 through Sec. 9.1 of the text plus lecture notes on semiconductors. There will also be questions on AC circuit phasor analysis and H( jω). This latter part, taking up the rest of the class period, will be counted separately and can help those who had low scores on the exam.You may refer to two 8 1/2" by 11" sheets of formulas, definitions and general information but not worked problems. You will be asked to turn in your sheets with your quiz (they will be returned). Bring your calculator.
  • For reference, here is Quiz 2 from 2008 (with solutions). Be sure you are up to date on BJT principles and circuits (including small-signal AC models).

Assignment 8 (Week 9):

• Read the lab writeup and notes on the BJT differential amplifier before coming to the lab.
• Read 9.3, 9.4.
• Problems due Monday, Nov. 30: 8.6, 8.8, 8.12, 9.21(use the simple small-signal model for the BJT which has r_e between E and B and the current source h_fei_b between B and C), 9.28, 9.39

Assignment 9 (Week 10):

• Read the lab writeup on feedback and oscillation before coming to the lab.
• Read 10.1-10.4.
  • You aren't responsible for the details of the inner workings of the LM741 op-amp in Sec. 10.2 but there are some useful concepts presented, so it is worth reading. Optional: you may be interested in reading Sec. 10.6 about RF communication.
• Lecture presentation material for the week of Nov. 30 has been placed in the class outline and here. This includes the material to be discussed on 12/2 and 12/4. The 2004 notes were left up, however (a bit of clean-up was done on pp. 10-11 of the Friday notes from 2004).
• Problems due Friday, 12/4/06: 8.40, 9.41, 9.55, 9.56, 10.35, 10.45, 10.58.
  Some notes on problems:
  • For 10.45, refer to the section on gain-bandwidth product on pp. 689-90; assume that R_L does not affect the amplifier gain
  • For 10.58, as with the Wien bridge oscillator in lab this week, the feedback network connects to the non-inverting input of the amplifier. The Barkhausen condition for oscillation, AB=-1, assumes negative feedback. So we have to provide the minus sign in the definition of B to get this relation. Thus, the expression in the problem should really be B=-(V₁/V₀).

Solutions for the first problem set have been posted in SmartSite Resources in the Solutions folder.
Office hours for this week are listed at the top of this page under the instructor name.

• CMS experiment at LHC:
  • CMS overview
  • CMS Times issue with article by Evan Friis on pixel test installation
• Harold Black and the Negative-Feedback Amplifier
• Nicola Tesla and the "war of the currents" between Edison.and Westinghouse.
  • PBS documentary on Tesla: home page
• Notes on complex frequency , s, poles of the transfer function, H(s), and Laplace transforms with figures.
• Early "spark gap" transmitters: (a) Spark Transmitters; (b) History of early spark transmitters and simulation of the waveforms of their transmissions.
  • Karl Ferdinand Braun, German physicist (1850-1918) invented the galena crystal point-contact diode (1874), the cathode ray tube and the oscilloscope (1897). He also made a number of key improvements to radio transmitters and receivers. He was awarded the Nobel Prize in physics (shared with Marconi) in 1909 for his work in wireless telegraphy. For information on Tesla's radio patents, see this link.
• A Java simulation of the Kronig-Penney model of wavefunctions in a one-dimensional periodic potential.
• Interesting recent developments:
  • Breakthrough for quantum measurement reported in using the capacitance of Josephson junctions to read out quantum bits.
  • First observation of the spin Hall effect by Awschalom, et al. at UCSB (Published in Science, 11 Nov. 2004). Use of the electron spin in electronic devices ("spintronics") is thought to be an important direction for advances in technology. For example, the spin-dependent giant magnetoresistance (GMR) is used for computer disk read heads.
• Information on Spice and personal computer versions:
  • Spice 3f5 self-study tutorials from Charles D.H. Williams at the University of Exeter.
  • Spice documentation in .pdf form: copyright notice, table of contents, document body
  • General Spice distribution from Berkeley (various systems: UNIX, MS-DOS, ...)
  • A more recent version of Spice for Linux/UNIX is known as ngspice. You can also look for rpm's of ngspice with rpmfind or Google.
  • PSPICE 9.1 Student Version (Windows) file still seems to be available here.
  • WinSPICE: Spice3 for Windows (including XP) from S.C. Wong of the Hong Kong Polytechnic University..
  • MacSpice 3f5 from Charles D.H. Williams, University of Exeter School of Physics. (for Mac OS X)
  • LTSpiceIV (for Windows; works under Wine on Room 106 Linux computers) from Linear Technology. Has a convenient GUI, works from schematics and has probing capabilities to view signals plus many other useful features.
• Transistorized!, a PBS program about transistors (explore the various links - includes demo of prototype point contact transistor).
• Some physicists who made inventions or advances in electronics (note that these advanced physics in most cases):
  • John Bardeen with Nobel prizes for the transistor and superconductivity theory;
  • Robert Noyce, co-(but separate) inventor of the integrated circuit (he was awarded the patent but Ted Hoff of Texas Instruments was awarded the Nobel Prize in 2000, too late for Noyce, who died in 1990, to be considered); co-founder of Intel;
  • Bruno Rossi, cosmic ray pioneer an d inventor of the Rossi coincidence circuit (first electronic "and");
  • Luis Alvarez, member of inventor hall of fame and Nobel physics laureate (elementary paticle physics).
• Test of jsMath: LaTeX markup for web pages via Javascript:
  • jsMath test page