Gas station without pumps

Circuits course: Table of Contents

This page collects all the blog posts for the development of my Applied Circuits for Bioengineers course.  The material distributed to the students in the course for the first offering of the course is on my University web pages:

The permanent web page for the course is

Because has an irrational prejudice against allowing oldest-first ordering of anything (or incompetent database programmers, which seems less likely), I’ve had to hand-create a table of contents for my posts about the Circuits Course. I would really love for them to have automatically generated “Table of Contents” summary pages for each category, giving the links to the posts and (optionally) the tags associated with the post.  Until they realize that not every reader and writer of blogs sees posts as being primarily valued by how recent they are, I’ll have to make do with this hand-generated table of contents (and remember to edit it every time I have a new post!):

  1. Changing teaching plans
  2. More on electronics course design
  3. Yet another project idea
  4. More musings on circuits course: temperature lab
  5. Buying parts for circuits course
  6. Oscilloscope practice lab
  7. Speakers and function generator
  8. Temperature lab, part2
  9. Temperature lab, part 3: voltage divider
  10. Op-amp lab
  11. Why teach circuits to bioengineers?
  12. What sensors for circuits class?
  13. Instrumentation amp lab
  14. Instrumentation amp, try 2
  15. Building a function generator kit
  16. Capacitive sensing
  17. Capacitive sensing, part 2
  18. Capacitive sensing with op amps
  19. Capacitive sensing with op amps, continued
  20. Phototransistor
  21. Synchronous demodulator
  22. EMG and EKG works
  23. Two-stage EKG
  24. EKG recording working
  25. Pulse detection with light
  26. Giving up on light-based pulse sensor
  27. More thoughts on EKG
  28. Looking at bioengineering measurements courses
  29. Cockroach electronics?
  30. Random thoughts on circuits labs
  31. EKG blinky
  32. Instrumentation amp protoboard
  33. Instrumentation amp protoboard rev2.1
  34. Trying to measure ionic current through small holes
  35. Medical Instrumentation, first 5 chapters
  36. Accelerometer for circuits course?
  37. Medical Instrumentation, chapter 6
  38. Conductivity of saline solution
  39. On stainless steel
  40. EKG blinky boards arrived
  41. More free textbooks
  42. Better measurement of conductivity of saline solution
  43. Measuring Ag/AgCl electrodes
  44. Order and topics for labs
    This post is a good one to start with, as it outlines the labs I’ve developed so far in the order we’ll probably do them and provides pointers to other posts about each lab.  There are no pointers to later posts, of course.
  45. EKG blinky boards work
  46. EKG blinky parts list and assembly instructions (Page, not Post)
  47. Instrumentation amp prototyping boards arrived
  48. Medical Instrumentation, Chapters 7 and 8
  49. Medical Instrumentation, Chapters 9–14
  50. Better electrode placement for EKG blinky
  51. Possible textbook, Horowitz and Hill
  52. EMG video
  53. All about circuits, a possible supplemental text
  54. Pressure sensing lab possibilities
  55. Wikipedia books, another approach for a free/cheap textbook
  56. PC board for pressure sensor
  57. Making Ag/AgCl electrodes
  58. Course approval forms
  59. Supplemental sheet for lab, draft 1 This post is obsolete, see draft 2 below.
  60. Supplemental sheet for lecture, draft 1
  61. Characterizing tactile transducer
  62. Characterizing tactile transducer again
  63. Bad news for circuits course
  64. Good news for circuits course
  65. New amplifier and shaker table
  66. Supplemental sheets, draft 2 This post provides an updated overview of the course, but no links to other posts.
  67. Filing the paperwork
  68. SBG and partner work in circuits class
  69. Circuits course as flipped Bloom’s
  70. Good and bad news for circuit course
  71. Pressure sensor assembly
  72. Pressure sensor miswired
  73. A way forward for circuit course
  74. Pressure sensor noise problems
  75. Rethinking the pressure sensor lab
  76. Thinking about PC boards and parts kits for circuits lab
  77. New PC board design for pressure sensor
  78. A different way forward for circuit course
  79. Notes for things to do on circuits course
  80. Capacitive sensing with Schmitt trigger
  81. Hysteresis lab
  82. Parts list for Applied Circuits W13, draft 1 (Page, not Post)
  83. New holder design for Ag/AgCl electrodes
  84. Holder for Ag/AgCl electrodes
  85. Updated things to do on circuits course
  86. Pressure sensor boards arrived
  87. Hysteresis board
  88. Small enrollment in circuits course
  89. Parts orders for Applied Circuits W13 (Page, not Post)
  90. Tested Python and Arduino installation
  91. Trying the oscilloscope practice lab
  92. FET threshold tests with Bitscope
  93. Disappointing power-amp lab
  94. Three lab handout drafts done
  95. Mic modeling lab too complicated
  96. Tools and parts list for Applied Circuits W13 (Page, not Post)  This page has the packing list (and prices) for the student tools-and-parts kit.  It looks like the kits will be $65 for Winter 2013.
  97. Parts packed, pressure sensors assembled, more thoughts on power amp
  98. Mic modeling lab rethought
  99. Data logging software for circuits course working
  100. FET modeling lab looking complicated
  101. Class D instead of class AB
  102. Class D works
  103. Parts and tools packaged today
  104. Updating to-do list
  105. More mess in the FET modeling lab
  106. Negative resistance oscillator
  107. First day of circuits class went ok
  108. More stuff bought for the circuits class
  109. Second day of circuits class
  110. First lab was too long
  111. Third day of circuits class
  112. Fourth day of circuits class
  113. Weekend work
  114. Fifth day of circuits class
  115. Second lab was smoother than the first
  116. Sixth day of circuits class
  117. Doing the hysteresis lab without a scope
  118. Seventh day of circuits class
  119. Electrode lab went well
  120. Eighth day of circuits class
  121. Virtual Community of Practice for circuits
  122. Ninth day of circuits class
  123. Teaching engineering thinking
  124. Formal reasoning in intro physics
  125. Tenth day of circuits class
  126. First soldering lab went fairly well
  127. Eleventh  day of circuits course
  128. Idea for phototransistor/FET lab
  129. Conjecture about gnuplot difficulties for students
  130. Quiz too long and too hard
  131. Positive moments
  132. Thirteenth day of circuit class and first op-amp lab
  133. Fourteenth day of circuits class
  134. Becoming engineers
  135. RC time constant lab
  136. Fifteenth day of circuits class
  137. Descaffolding
  138. Sixteenth day of circuits class
  139. Tinkering lab
  140. Seventeenth day of circuits class: inductors and gnuplot tutorial
  141. Teaching students to build and use models
  142. All weekend and handouts still not written
  143. Pressure-sensor lab handout written
  144. Eighteenth day of circuits class
  145. Sampling lab went ok
  146. Nineteenth day of circuits class
  147. Class D with LC filter works
  148. Tinkering lab reports show problems
  149. Twentieth day of circuits class
  150. Better model for loudspeaker
  151. Twenty-first day of circuits class
  152. Pressure-sensor lab went well
  153. Rethinking the power-amp lab again
  154. Rethinking the power-amp lab yet again
  155. Quiz 2, better than quiz 1
  156. Twenty-second day of circuits class (actually 23rd, I forgot to count the quiz day)
  157. Twenty-third day of circuits class  (actually 24th)
  158. Class-D power amp lab went smoothly
  159. Twenty-fifth day of circuits class
  160. Twenty-sixth day of circuits class
  161. Exploding electrolytic capacitors
  162. Tried EKG design on protoboard
  163. Action potential lecture and EKG lab
  164. Twenty-eighth day of circuits class
  165. Last day of circuits class
  166. Bar exam for circuits class

The next set of posts are all after the first offering of the course, and include thoughts on how things went and possible different labs to try.

  1. Student writing
  2. Triangle-wave oscillator
  3. Self-taught teacher
  4. Supplemental sheets, draft 3
  5. Showing is better than telling, but not by much
  6. Sounds like my course
  7. Teaching by hand
  8. Kemet tech reports on capacitors
  9. Pressure sensor with air pump
  10. Blinky EKG hard to debug
  11. Blinky EKG fixed
  12. Disseminating the applied circuits labs
  13. 2-op-amp instrumentation amp
  14. 3-op-amp instrumentation amp
  15. Common-mode noise in EKG
  16. Some failed designs
  17. Logarithmic amplifier
  18. Logarithmic amplifier again
  19. Still more on log amplifiers
  20. Precision rectifier
  21. Improved rectifier
  22. Improved rectifier with Schottky diodes
  23. Freedom KL25Z board
  24. Virtual ground circuits
  25. Optical pulse monitor with little electronics
  26. Digital filters for pulse monitor
  27. Failed attempt at pulse oximeter
  28. Microphone sensitivity exercise
  29. MPX2053DP pressure sensor being discontinued
  30. Service courses
  31. Towards automatic measurement of conductivity of saline solution
  32. Broken soldering iron
  33. More on automatic measurement of conductivity of saline solution looks at waveforms for square waves generated using PWM on the KL25Z board. In this post I found that 100kHz square waves would work well.
  34. Still more on automatic measurement of conductivity of saline solution looks at waveforms for bursts of square waves generated by an Arduino board. The bursts are limited to about 4kHz, but that may be good enough for a conductivity meter.
  35. Using KL25Z for measuring salinity shows a program on the KL25Z that averages readings during the last 10,000 pulses of a 50,000-pulse burst. It has Gaussian noise with a standard deviation of about 0.13mV on a 2.8v signal. Jostling the electrodes is visible in the traces.
  36. Range of conductivity measurements adds measurement of the applied voltage to the program (reducing the frequency to 65kHz) and checks the linearity of the conductance with concentration of NaCl, which is not very good on this simple 3-point measurement at 0M, 0.1M, and 1M NaCl.
  37. Designing courses to teach design has notes for a lightning talk I need to give next week about the creation of this course (among other things).
  38. Designing courses to teach design—draft 2 gives a complete draft for the lightning talk (a couple days in advance of the talk itself).
  39. Wire loop vs. twisted pair try 1 discusses trying to detect the difference between a twisted pair and a loose loop, but goes about it the wrong way, detecting capacitive rather than inductive coupling.
  40. Tools and parts list for Applied Circuits S2014 lists all the parts and prices (without tax and shipping charges) for Spring 2014 course.
  41. Lying to my students is about errors I’ve made in presenting photodiodes to the freshman design seminar.  Some of the errors were intentional simplifications, but some were just errors.
  42. More on loudness circuits puts together a preamp, a peak detector, and a log amplifier to make a loudness sensor.  I’ve not tried building the circuit yet, so it is just a theoretical design.
  43. Better I-V plot for Schottky diodes fixes the plot from the “More on loudness circuits” post and fits the theoretical model for over 120dB range of current.
  44. I-vs-V plots for base-emitter diodes provides voltage-vs-current plots for the base-emitter diodes of S9012 PNP and S9013 NPN transistors.
  45. Still better I-V plot for Schottky diodes uses the 16-bit ADC in the KL25Z and a couple of circuit tricks to get much cleaner I-V plots for the Schottky diodes from 1nA t0 10mA.
  46. Diode-connected nFET characterisitics tests the AOI518 nFETs that we’ll be using this year using the KL25Z. I tested the flyback diode also, up to 1A.
  47. Soldering headers on a Freedom board is a tutorial on soldering headers onto a KL25Z (or KL26Z) board.  It is needed for the new first day of lab.
  48. Plan for rearranged circuits labs is a tentative schedule for the labs for the Spring 2014 offering of the course
  49. Updates on some earlier lessons updates the lessons at the end of Still better I-V plot for Schottky diodes.
  50. New phototransistor lab is a re-examination of an optical pulse monitor.  It looks doable, but only as a 2-day lab, which will mean rescheduling.
  51. Revised plan for circuits labs is a rework of the schedule to accommodate the longer, more complicated phototransistor lab.
  52. What makes teaching programming difficult? discusses the problem of teaching problem decomposition and debugging, with some ideas for how to improve it in both the freshman design seminar and the applied circuits course.
  53. Panicking about circuits class discusses what I’ve done and have left to do before classes start tomorrow.
  54. New modeling lab for electret microphone shows how I’m changing the first microphone lab to adapt it for the KL25Z boards.
  55. First day of S14 circuits class went ok talks about the first day of the circuits course—panic mode is still firmly in place.
  56. Thermistor lab 1 stressful, but successful talks about the first lab of the quarter.  It ended up OK, but was a bit stressful for me.
  57. Gnuplot demo describes the first gnuplot tutorial.
  58. Thermistor lab second half took too long talks about the Thursday lab running 5.5 hours, instead of 3, and what I think I can do next year to fix the problem.
  59. Third day of circuits class was low key talks about getting the students back to equilibrium after the too-long lab.
  60. Hysteresis lab on KL25Z describes new KL25Z code for looking at the frequency changes of a relaxation oscillator used in the hysteresis lab.
  61. Feedback on first lab report mainly talks about the problems I saw in the first design reports from this year’s class.
  62. First mic lab slightly too long talks about the first microphone lab (DC characterization of the mic).
  63. Protein essentials and second gnuplot demo talks about two different lectures: a guest lecture in another class on protein structure and the second gnuplot demo in the applied circuits class. I also had some metacognition material on the zone of proximal development and imposter syndrome.
  64. Second mic lab went well sums up the second half of the mic lab, in which students added a load resistor and looked at the mic output on the oscilloscope.
  65. Impedance, finally describes the chalkboard lecture on complex impedance, which went well.
  66. Designing courses to teach design—draft 3 is an updated version of my talk “Designing Courses to Teach Design”.
  67. Hysteresis lecture talks about the lesson on hysteresis.
  68. Hysteresis lab too long (do you detect a theme of labs running too long?)
  69. Between halves of the hysteresis lab talks about the lecture covering work students had already done.
  70. Hysteresis lab ended well talks about finishing up the hysteresis lab and the shortage of board holders for soldering.
  71. Voltage dividers, parallel impedance, scope probes covers the content of the lecture after the hysteresis lab.

I should probably annotate every listing above with a sentence or two about what is in the post, as well as collecting posts into separate thematic groups below.

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