Electronics course: Table of Contents

This page collects all the blog posts for the development of my Applied Analog Electronics 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: http://users.soe.ucsc.edu/~karplus/bme194/w13/

The permanent web page for the course is http://users.soe.ucsc.edu/~karplus/bme101/ or http://users.soe.ucsc.edu/~karplus/bme51/

Because WordPress.com 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!).

I should probably annotate every listing with a sentence or two about what is in the post, as well as collecting posts into separate thematic groups below.  For now, the first couple hundred posts don’t have explanatory sentences.

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 labsThis 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.

167. Student writing
168. Triangle-wave oscillator
169. Self-taught teacher
170. Supplemental sheets, draft 3
171. Showing is better than telling, but not by much
172. Sounds like my course
173. Teaching by hand
174. Kemet tech reports on capacitors
175. Pressure sensor with air pump
176. Blinky EKG hard to debug
177. Blinky EKG fixed
178. Disseminating the applied circuits labs
179. 2-op-amp instrumentation amp
180. 3-op-amp instrumentation amp
181. Common-mode noise in EKG
182. Some failed designs
183. Logarithmic amplifier
184. Logarithmic amplifier again
185. Still more on log amplifiers
186. Precision rectifier
187. Improved rectifier
188. Improved rectifier with Schottky diodes
189. Freedom KL25Z board
190. Virtual ground circuits
191. Optical pulse monitor with little electronics
192. Digital filters for pulse monitor
193. Failed attempt at pulse oximeter
194. Microphone sensitivity exercise
195. MPX2053DP pressure sensor being discontinued
196. Service courses
197. Towards automatic measurement of conductivity of saline solution
198. Broken soldering iron
199. 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.
200. 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.
201. 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.
202. 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.
203. 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).
204. Designing courses to teach design—draft 2 gives a complete draft for the lightning talk (a couple days in advance of the talk itself).
205. 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.
206. Tools and parts list for Applied Circuits S2014 lists all the parts and prices (without tax and shipping charges) for Spring 2014 course.
207. 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.
208. 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.
209. 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.
210. 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.
211. 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.
212. Diode-connected nFET characteristics tests the AOI518 nFETs that we’ll be using this year using the KL25Z. I tested the flyback diode also, up to 1A.
213. 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.
214. Plan for rearranged circuits labs is a tentative schedule for the labs for the Spring 2014 offering of the course
215. Updates on some earlier lessons updates the lessons at the end of Still better I-V plot for Schottky diodes.
216. 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.
217. Revised plan for circuits labs is a rework of the schedule to accommodate the longer, more complicated phototransistor lab.
218. 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.
219. Panicking about circuits class discusses what I’ve done and have left to do before classes start tomorrow.
220. New modeling lab for electret microphone shows how I’m changing the first microphone lab to adapt it for the KL25Z boards.
221. First day of S14 circuits class went ok talks about the first day of the circuits course—panic mode is still firmly in place.
222. 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.
223. Gnuplot demo describes the first gnuplot tutorial.
224. 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.
225. Third day of circuits class was low key talks about getting the students back to equilibrium after the too-long lab.
226. Hysteresis lab on KL25Z describes new KL25Z code for looking at the frequency changes of a relaxation oscillator used in the hysteresis lab.
227. Feedback on first lab report mainly talks about the problems I saw in the first design reports from this year’s class.
228. First mic lab slightly too long talks about the first microphone lab (DC characterization of the mic).
229. 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.
230. 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.
231. Impedance, finally describes the chalkboard lecture on complex impedance, which went well.
232. Designing courses to teach design—draft 3 is an updated version of my talk “Designing Courses to Teach Design”.
233. Hysteresis lecture talks about the lesson on hysteresis.
234. Hysteresis lab too long (do you detect a theme of labs running too long?)
235. Between halves of the hysteresis lab talks about the lecture covering work students had already done.
236. Hysteresis lab ended well talks about finishing up the hysteresis lab and the shortage of board holders for soldering.
237. Voltage dividers, parallel impedance, scope probes covers the content of the lecture after the hysteresis lab.
238. Designing courses to teach design—draft 4 is my 4th attempt at writing my talk “Designing Courses to Teach Design”.
239. Electrodes and load lines lists the topics of the 10th lecture and briefly mentions my dilemma about whether to assign more homework.
240. Stainless steel electrode lab went fairly well discusses the first half of the electrodes lab.
241. Stainless steel electrode analysis talks about the gnuplot analysis of the stainless steel electrode data.
242. Ag/AgCl electrode lab went fairly well describes the second half of the electrodes lab, and what should be done differently.
243. As expected, students did poorly on the quiz analyzes the quiz results, which were just as bad as I expected, though I was hoping for better this year.
244. Loudspeaker lab describes the lab for measuring the loudspeaker impedance as a function of frequency.
245. Loudspeaker analysis describes the gnuplot analysis of the data collected in the loudspeaker lab, and a little on quantization of values and time.
246. Sampling and aliasing lab describes that lab, and the weird data collected for one loudspeaker in the earlier loudspeaker lab.
247. Video of Designing Courses talk gives the link to a video of my Designing Courses talk.
248. First op amp lecture summarizes the points of the first lecture on the third main theme of the course: op amps.
249. Block diagrams and audio amps talks about developing a block diagram for a simple audio amplifier using op amps.
250. Audio amp lab talked about the audio amplifier lab (which turned out to be almost 100% prelab, since the students hadn’t done their work ahead of time).
251. Quiz corrections covers the quiz results and redo as a homework assignment, also describing the multistep problem in the audio amp design.
252. Low-power audio amp lab completed talks about finishing the simple audio amp lab, and some changes I should make for next year.
253. Second op amp lecture describes a class covering virtual grounds, gain-bandwidth product, and transimpedance amplifiers—a bit too much for one class.
254. Lecture for pulse monitor talks about the lecture before the pulse-monitor lab and my disappointment with how few students attempted the prelab assignment over the weekend.
255. Answer getting talks about a mindset problem that a lot of my students suffer from.
256. Phototransistor lab talks about the first half of the optical pulse detector lab.
257. Mixed topics in lecture talks about active filters and the second stage of the optical pulse monitor, along with doing prelabs, answer-getting, tinkering, and other meta topics.
258. Very long time in the lab talks about my longest time in the circuits lab so far: 2p.m.–9:30p.m.
259. Problems rewriting the Class-D amplifier lab talks about the difficulties I’ve been having with rewriting the class-D power amp lab.
260. Instrumentation amp lecture has very short notes about last Friday’s lecture.
261. Long weekend talks about what I’m doing to fix the class-D amplifier lab, what I saw in the lab reports for the optical pulse detector, and what I covered in lecture today.
262. Class-D lab revision didn’t work covers both halves of the pressure-sensor amp lab and the quiz between them—it also talks about my attempt to fix the class-D lab, which turned out to be worse than the original, which I am returning to.
263. Class-D amplifier lecture 2 talks about a rather rushed lecture before Memorial Day weekend.
264. Cardiac action potential talks about the only real “bio” lecture of the course.
265. Class-D amplifier lab done, EKG block diagrams begun talks about the labs this week, today’s class, and possibility of turning my lab handouts into a textbook for the course.
266. Grading big stack of “redo” assignments talks about near-end-of-term grading, and policy changes I plan for next year.
267. Blood pressure monitor describes a possible modification to the pressure sensor lab next year.
268. EKG lab not quite done talks about the first half of the EKG lab, where most students almost finished the whole lab.
269. Random topics in class today has random topics from the penultimate lecture of the course.
270. Very long lab time today talks about the last scheduled lab day of the quarter.
271. Wrapping up Applied Circuits and PteroDAQ bug fix covers the last day of class as well as a bug fix that my son made to the PteroDAQ code this week.

The next group of posts will be preparing for and reporting on the third offering of the course:

272. Digi-key end-of-life notification for IR emitter talks about changes in which LEDs will be used next year.
273. Starting on book for circuits lab—scheduling labs talks about a possible schedule of labs for next year.
274. Zeroth draft of book done reports on initial progress on the text book.
275. Loudspeaker relaxation oscillator talks about using a loudspeaker as the feedback element in a Schmitt-trigger relaxation oscillator.
276. Instrumentation amp from op amps still fails talks about the possibility of using the cheap op-amp chips instead of the more expensive instrumentation-amp chips for the pressure sensor lab.  Bottom line: No, but maybe for the EKG?
277. Instrumentation amp from op amps fine for EKG shows the homemade inst amp from MCP6004 op amps working ok for the EKG.
278. Faculty writing community reports on an idea for a faculty writing group that might have helped me get more writing done last summer.
279. How big is a course? talks about how many hours a course should take up, both contact hours (lecture, lab, individual meetings) and homework.
280. Tools and parts list for Applied Circuits S2015 lists the parts (with prices) that we’ll be using this year.
281. First day of S15 circuits class: demo failure talks about the first day of class for Spring 2015.
282. First lab for Spring describes the first lab (soldering) for S15.
283. Second lecture in Spring 2015 electronics talks about the lecture on sampling and a bit about getting PteroDAQ to work on new machines.
284. Moving sampling lab early was a good idea talks about having scheduled the sampling and aliasing lab much earlier this year.
285. Third lecture: resistance and voltage dividers describes the main content of the first pure chalk talk of the quarter, and describes the cold calling I use.
286. Temperature lab went well talks about smooth running of the first thermistor lab.
287. Optimization and model fitting went well today talks about the optimization problem from the first homework and model fitting with gnuplot.
288. Second half of temperature lab went well continues the trend of successful labs.
289. Sinusoids and impedance lecture discusses the 6th lecture of Spring 2015, leading to the impedance of capacitors and RC filters.
290. Too much prelab homework for microphone lab talks about grading the pre-lab homework for the microphone lab.
291. Microphone labs went OK talks about the microphone lab and the lecture between halves of the lab
292. Loudspeaker lab went well talks about the two lectures before the loudspeaker lab, and the 1-day loudspeaker lab itself.
293. Very long couple of days talks about the lecture between the loudspeaker and hysteresis labs, the hysteresis lab, and a generally stressful few days.
294. Email exchanges with the electronics class includes a couple of e-mail exchanges with the class, about due dates and about material that was asked in a question but not covered in the book or in class yet.
295. Comments for class after grading talks about observations made after the latest round of grading (the loudspeaker and hysteresis lab design reports).
296. Ideas for improving hysteresis lab talks about ideas for improving the hysteresis lab, but it’s not clear there is room in the schedule for expanding it back to a 2-day lab.
297. More model fitting in lecture talks about modeling the stainless-steel electrodes, introducing a new “semicapacitor” model for the electrodes, but without showing the plots of the model fitting data.
298. Welded welding rod shows a picture of a corrosion ring on one of the stainless-steel electrodes, that looks like the rods are welded together before being drawn down to 1/8″.
299. Ag/AgCl electrode lab went ok talks about the second electrode lab, surprises from the substitution of a different brand of EKG electrode, and how voltmeter input impedance interferes with the impedance calculations we’ve been doing.
300. First op-amp lab was quick talks about the lecture setting up the block diagram for the low-power audio amplifier and the first op-amp lab.
301. Voltmeter impedance talks about measuring the input impedance of AC voltmeters.
302. Lecture in middle of first op-amp lab talks about not giving a midterm quiz this year and about the second half of the first op-amp lab.
303. First instrumentation-amp lecture talks about the first instrumentation-amplifier lecture (there will be more) for Spring 2015.
304. Lecture on pressure sensors talks about the lecture on pressure sensors—actually more about some of the problems I saw in the audio-amplifier design reports.
305. Checking on my pedagogy reports on how I think I’m doing against a checklist that Mark Guzdial provided for teaching programming to beginners.
306. Blood pressure lab talks about the blood pressure lab and the lecture between the two halves of the lab. The students in the lab needed more scaffolding than I would like this late in the quarter.
307. Blood pressure lab part 2 talks about the second half of the blood pressure lab, which took longer than I expected.
308. Pulse monitor lecture and lab talks briefly about the one lecture I gave on transimpedance amplifiers and photodetectors, in preparation for the optical pulse monitor lab this week, then talks about the rather miserable lecture I gave on real power and pulse-width modulation, and the not very productive time in the first half of the pulse monitor lab.
309. Pulse monitor lab part 2 and power-amp lecture talks about the second lecture on PWM and class-D power amps, and the second half of the pulse monitor lab, both of which were more successful than the first half of the week.
310. Interesting observation with PteroDAQ has an interesting observation students made in class involving aliasing.
311. Third power-amp lecture and first half of lab discusses the power amp lectures and lab, with some mention of Miller plateaus when switching FETs.
312. Last power-amp lecture talks about choosing pull-up resistors for the comparators in the class-D amplifier lab, and suggests some material to add to the book.
313. Power amps working talks a bit about the end of the power-amp lab with some ideas for future improvement. It also looks at Miller plateaus recorded by the Tektronix digital scopes.
314. Two lectures: Jellyfish and EKG talks about the 2-op-amp instrumentation amp and EKG lecture (Jellyfish is in there from a different lecture earlier in the day).
315. Reducing 60Hz interference talks about changing the filter limits for the pulse monitor to reduce 60Hz interference.
316. Confidence and not opting out talks about confidence as a gender-related cause of different academic outcomes and about my frustration with not being able to reach students at the bottom of the class.
317. Crude theremin talks about rescuing the EKG demo, and about a lecture on how theremins work.  I also give an example of a crude theremin design that doesn’t quite work.
318. Last lab of Spring 2015 talks about my longest lab day yet (about 11 hours in the instructional lab today), and about what I plan to discuss in class tomorrow.

After Spring 2015, it is time once again to review all the labs and rewrite book chapters. I want to try to add more at-home labs, so that hobbyists can use the book without $1000s of equipment, and so that students can do some of the work in their dorm rooms and apartments.

318. 318. Bitscope jitter and nFET Miller plateau talks about a way to get much higher time resolution for repetitive signals using the Bitscope USB oscilloscope, applying it to the gate voltage of an nFET to show the Miller plateau.
     319. Update for nFET Miller plateau gives the test jig used for the Bitscope jitter post, and talks a bit about how I might change things for a plot for the book.
     320. More on nFET Miller plateau gives an improved test jig and the resulting plot for the book, but also expresses some concerns about the miscalibration of the offsets in the Bitscope BS10 USB oscilloscope.
     321. PteroDAQ bug fix talks about a bug fix for the PteroDAQ data acquisition software written for the course, where data was being corrupted at higher sampling rates.
     322. FG085 function generator talks about a new function generator kit I assembled—one that may be useful for an at-home hobbyist lab for the course.
     323. FG085 function generator output impedance measures the output impedance of the FG085, finding it to be just under 47Ω, rather than 50Ω.
     324. Pullup vs. transimpedance amplifier discusses the advantages of a transimpedance amplifier over a simple pull-up resistor (speed!).
     325. Measuring voltmeter input impedance measures the voltmeter impedance in a much simpler way than the Voltmeter impedance post.
     326. Testing nFET with function generator reports i-vs-v curves for the PSMN022-30PL nFET when it is diode-connected, and finds a negative dynamic resistance.
     327. Testing nFET body diode with function generator continues the previous post by characterizing the body diode of the PSMN022-30PL nFET.  It also discusses some limitations of the FG085 function generator.
     328. Negative resistance in nFETs provides a conjecture (not complete) about where the negative resistance in nFETs is coming from.
     329. Improving PteroDAQ looks at the multi-platform (KL25Z and Arduino) version of PteroDAQ that I hope to have ready for beta release by the end of summer.  It looks in particular at the sampling frequencies obtainable and the noise in unaveraged ADC reads on the KL25Z board.
     330. PteroDAQ v0.2b1 released! announces the new vastly improved version of the PteroDAQ data-acquisition system.
     331. PteroDAQ board calibration reports measurements of the accuracy of the bandgap voltage references on 5 boards used with the PteroDAQ system.
     332. FG085 function generator bugs reports bugs I’ve found in the FG085 function generator (including summarizing some from previous posts).
     333. Reworking electronics class for cheap equipment talks about plans to make more of the applied electronics course doable at home for students and autodidacts.
     334. DT-9205A voltmeter review is a review of the $10 DT-9205A digital multimeter, concluding that it is probably good enough for students to do all the labs in the course.
     335. Measuring BitScope BS-10 input impedance measures the input impedance of the BitScope BS-10 USB oscilloscope at 1MΩ || 10pF.
     336. Measuring PteroDAQ KL25Z input impedance summarizes the previous AC voltmeter measurements and measures the input impedance of the KL25Z single-ended ADC.
     337. More on measuring PteroDAQ KL25Z input impedance talks about some problems in measuring the KL25Z input impedance, having to do with using too high a source impedance.
     338. Noise from PteroDAQ KL25Z clears up the mess on PteroDAQ KL25Z input impedance by realizing that the limiting factor isn’t the impedance, but noise injected back into the circuit by the sample-and-hold circuitry.
     339. Getting KL25Z bootloader to work without Windows 7 talks about workarounds for the ridiculously bad Bootloader on the KL25Z boards, which only works with Windows 7. There are pointers to workarounds for WIndows 8 and for Linux, but I’ve yet to find one for Mac OS X.  The new v1.11 Bootloader from P&E Micro does not work with Mac OS X, despite their claims.
     340. Ordered first Windows computer I finally broke down and am buying a cheap WIndows 8.1 machine, just to test the PteroDAQ software and installation instructions on Windows 8.
     341. Lean publishing talks about a model close to self publication that I might try out for the textbook.
     342. Book draft available online announces the pre-release of book drafts on https://leanpub.com/applied_electronics_for_bioengineers
     343. Draft book cover shows my first place-holder version of a cover for the book.
     344. Textbook should be on paper discusses the economics of producing a print-on-demand version of the book.  This does not look particularly feasible for the next year.
     345. PteroDAQ supports Teensy 3.1 describes releasing Teensy 3.1 support for the PteroDAQ data acquisition system.
     346. PteroDAQ boards shows a picture of the Teensy 3.1 beside other boards that PteroDAQ supports, and discusses the tradeoffs in deciding which board to require for the class.
     347. Leanpub is a very small publisher gives a few statistics about Leanpub, the company I’m distributing pre-releases of my book through.
     348. PteroDAQ will support Teensy LC mentions plans to support the Teensy LC and use it for the class.
     349. Teensy LC support for PteroDAQ written but not tested compares code sizes for the firmware for PteroDAQ on different platforms.
     350. Teensy LC support for PteroDAQ working, but it took me longer than I expected.
     351. Arduino-compatible software for FRDM-KL25Z board describes one project I found that does not do what I want for Arduino IDE support of the FRDM KL25Z board.
     352. Bitscope function generator review describes the Bitscope’s BS10 function generator—not very flatteringly.
     353. LED I-vs-V curves gives I-vs-V curves for several of the LEDs I have on hand.
     354. PteroDAQ frequency channels talks about the beginnings of frequency measurements for the PteroDAQ data acquisition system.
     355. PteroDAQ frequency channels on FRDM-KL25Z talks about refactoring the PteroDAQ GUI code and adding frequency channels for theFRDM-KL25Z boards.
     356. DMA counter for event counting on Freescale Kinetis processors discusses my frustration with trying to get longer than 15-bit counts for frequency channels on the Teensy 3.1 (K20 processor) in PteroDAQ.
     357. Book draft 2015 Aug 28 mentions the changes in the most recent draft book release, as well as listing some tasks I have to complete that will be competing for writing time.
     358. Pedagogy for bioinformatics teaching mainly talks about the bioinformatics course BME 205, but has some mention of teaching gnuplot in the electronics course.
     359. Softcover: another self-publishing house mentions another possible self-publishing house, as an alternative to Leanpub.  Currently, I plan to stick with Leanpub.
     360. Calibrating PteroDAQ frequency measurements talks about checking the accuracy of frequency measurements with PteroDAQ, determining that the FG085 function generator uses crummy crystals, but that the three boards tested all had crystals within ±30ppm. A bug fix for PteroDAQ frequency channels was suggested.
     361. Breath pressure measurements talks about my first attempts at breath-pressure measurement apparatus cheap enough for the lab.
     362. Microphone preamplifier shows a picture of a microphone preamp wired on the new op-amp prototyping board, together with PteroDAQ traces of the microphone, low-gain, and high-gain voltages.
     363. Gamifying a course talks about why I’ve not “gamified” the electronics course.
     364. Book draft 2015 Sep 7 lists the changes for the most recent release of the book.
     365. Class-D power amp lab revamp talks about changes I’m contemplating for the class-D amplifier lab, to simplify the design work and make it more easily done in a home lab.
     366. H-bridge Class-D works is just what it sounds like—I tried out the Class-D lab with a single-power-supply design and a cMOS H-bridge, and that approach works well. It should be much easier for the students to do than the thee power supplies, open-collector comparators, and resistor tweaking we’ve been doing.
     367. H-bridge Class-D hum problem solved explains the unexpected solution to the hum problem of the previous post.
     368. Teensy 3.2 available serves as a reminder to myself to update PteroDAQ to support the Teensy 3.2 board (same as Teensy 3.1, but with more current available from the 3.3V regulator).
     369. AOI514 nFET I-vs-V plots the measurements I made on the AOI514 nFET, but I decided the plot was too messy to include in the book.
     370. Considering splitting Applied Electronics course discusses a possible redesign from a 1-quarter 7-unit course to 2 4-unit courses.
     371. Meeting for teachers of writing to engineers is informal notes from an informal meeting I organized of people who teach engineering students writing.
     372. Resistor assortment box is a description and photo of the box I’m now using for keeping my resistor assortment sorted.
     373. Sabbatical plans for 2016–17 follows up on Considering splitting Applied Electronics course—I am going to split the course next year.
     374. Sabbatical leave application 2016 is my first musings on what I’ll put on the form for applying for sabbatical leave Fall 2016.
     375. Tools and parts list for Applied Electronics S2016 Page of parts and tools.
     376. New tools and parts list for applied electronics announcement on the blog of the new page of parts and tools.
     377. Small updates to book announces update for electrodes chapter and lab.
     378. Syllabi for splitting Applied Electronics into two courses provides the first drafts of the syllabi for the proposed split of the course that should start in Winter 2017.
     379. Counting pages discusses the page count of my textbook and compares it to a couple of other textbooks in different fields.
     380. Optical pulse monitor software discusses doing real-time software for an optical pulse monitor—most of the other discussions have talked only of the hardware with post-processing of PteroDAQ recordings.
     381. Oscilloscope tutorial video introduces an oscilloscope tutorial I filmed for the class.
     382. Class topic not what was planned discusses the second lecture of Spring 2016, where I gave a totally different lecture than what I had planned.
     383. Pep talk for students frustrated at the end of the first week talks about how Lab 2 ended up much more challenging than intended, and a bit about what I’m going to have to do to make sure the students don’t get too discouraged.
     384. PteroDAQ bug fixes talks about missing lunch to debug PteroDAQ in time for the second lab section.
     385. YouTube closed captions are awful provides the automatically generated closed captions for the oscilloscope video.  They are so bad, that they’re funny.
     386. Transfer of learning talks about the difficulty in teaching students to learn to solve problems different from the ones in class.
     387. Santa Cruz Mini Maker Faire went well talks about my display at the Santa Cruz Mini Maker Faire, which showed off several of the projects from the course.
     388. Revised microphone pre-amp lab too long talks about my usual failure—a lab that took longer than I had planned.
     389. Miswiring errors continues a discussion started in the comments of the previous post.
     390. Revised pressure sensor lab went very well describes the success of the new variant of the pressure-sensor lab.
     391. Don’t put pulse monitor first talks about some difficulties with the transimpedance amplifier lab.
     392. 2016 T-shirts ordered shows the design for this year’s T-shirt and discusses the local T-shirt printing companies a little.
     393. Disappointing class-D amplifier reports talks about the design reports for the Class-D power amplifier lab, which had an 80% or higher redo rate.
     394. End of quarter feedback discusses feedback from the students at the end of the quarter.
     395. Teaching writing lab reports talks in general terms about writing problems in the stack of grading I’ve been slogging through, with pointers to a post by Greg Jacobs about grading AP Physics exams.
     396. Pulse monitor with log-transimpedance amplifier gives a (not-very-good) circuit for a pulse monitor using a log-transimpedance amplifier
     397. Flipped Learning talks a bit about the small amount of “flipped learning” in the applied electronics course.
     398. Capacitance meter using touchRead() discusses using the touchRead() routine in Teensyduino to measure capacitance up to 1nF.
     399. Autoranging capacitance meter using TeensyLC gives the code for an autoranging capacitance meter using the TeensyLC to talk to a USB serial monitor.
     400. Possible new FET lab for electronics course describes drain-source resistance vs gate voltage plots for nFETs, as a possible addition to the class-D amplifier lab.
     401. pFET Ron_vs_Vgs completes Possible new FET lab for electronics course by measuring drain-source resistance vs gate voltage plots for pFETs.
     402. More thoughts on measuring FETs continues the analysis of the possible FET measurement lab.
     403. Measuring a high-voltage nFET gives Id-vs-Vgs and Power-vs-Vgs curves for an nFET we plan to use in theater lights.
     404. Why my nFET measurements were bad explains why the results in the previous 4 or 5 posts were bad—Vds has a minimum value!
     405. STM32F103C8T6 development board mentions a cheap new development board which I’m considering adding to the PteroDAQ family, but not planning to use for the course.
     406. The real reason my nFET measurements were bad corrects Why my nFET measurements were bad, which had an incorrect explanation of my bad measurements, and provides a circuit and clean Id-vs-Vds plots.
     407. Possible new lab order describes the new order I’m proposing for labs in changing the course to a 2-quarter sequence. (The order also makes sense for 1-quarter or 1-semester course, I think.)
     408. Digilent Analog Discovery 2 USB Oscilloscope provide pointers to a new USB oscilloscope that I’m considering getting.
     409. More thoughts on log-transimpedance for pulse monitor lab gives a different model for diodes than the standard one, which changes a log amplifier into an I^⅛ amplifier.
     410. Transimpedance pulse monitor does need low-pass adds low-pass filters to the second and third stages of the log-transimpedance amplifier.
     411. Using nFET body diode for log-transimpedance has V-vs-I plots for a body diode of a power nFET (with very nice log behavior over 7.5 decades or more) and uses the body diode as the transimpedance feedback element.
     412. Using 4¢ diode for log-transimpedance has V-vs-I plots for a couple of general-purpose diodes and debugs a problem with using them in a log-transimpedance amplifier for a pulse monitor.
     413. Pulse monitor using log amplifier talks about some changes to the pulse monitor lab for the new lab order and checks the step response of the logarithmic light sensor. It includes pictures of wooden blocks for use with ambient light illumination and cis illumination (LED on same side of finger as phototransistor).
     414. Tools and parts list for Applied Electronics W2017 and S2017 gives the parts list for the 2017 offering of the course (as BME 51A and 51B).
     415. Release notes for book (Oct 2016) is the release notes for the latest draft of the book.
     416. Lego as LED holder talks about drilling Lego bricks to make the holder for cisillumination for a pulse monitor.
     417. Lego as LED holder revisited shows a better approach for using drilled Lego bricks for the optical pulse monitor.
     418. Electronics course over-enrolled expresses my surprise at the rapid enrollment growth in the course.
     419. Black Friday sale 2016 announces a sale on my book.
     420. Cyber Monday sale 2016 gives the results of the Black Friday sale and the continuation of the sale through Cyber Monday.
     421. Electret mic DC characterization with Analog Discovery 2 redoes the electret microphone DC characterization lab, using the Analog Discovery 2 oscilloscope and function generator.
     422. Two-electrode vs. four-electrode impedance spectroscopy looks at two ways of measuring bulk electrical properties of solutions, using the network analyzer of the Analog Discovery 2 oscilloscope.
     423. FET I-vs-V with Analog Discovery 2 again is another post in the series about the Analog Discovery 2 USB oscilloscope (not all of which are in this table of contents).  This one looks at DC characterization of nFETs, and the difficulty of doing this well with breadboard circuits.
     424. Headphone impedance with Analog Discovery 2 looks at headphone impedance and suggests that the audio preamplifier lab should be tested with earbud headphones as loads, rather than loudspeakers, as the headphones would be loud enough to hear distortion and other problems.
     425. Thermistor lab graded talks about the common writing problems for the first lab report of the course.
     426. Units matter talks about my frustration with many students not being able to do arithmetic with units.
     427. Hysteresis oscillator is voltage-dependent looks at how the frequency of the hysteresis oscillator board changes with power supply voltage.
     428. More writing advice from the electronics course gives some of the writing feedback on the hysteresis-oscillator lab.
     429. Understanding semilog plots talks about my discovery that engineering students don’t know how to read semilog plots.
     430. Electret microphone hysteresis talks about the hysteresis in the I-vs-V plots for electret microphones
     431. Co-instructor wanted for applied electronics course is an unofficial job ad for a co-instructor position for the applied electronics course in 2018.
     432. Maybe eliminate bench equipment next year asks for advice on two different approaches to equipping student labs next year.
     433. New problem in class-D lab talks about nFETs popping out of breadboards.
     434. Midterm quiz doesn’t tell me much new gives scatter diagram showing that the midterm scores are highly correlated with the homework scores, and that it really is true that half the class doesn’t understand the basics.
     435. Kind thoughts from a student quotes an email message from one of my students.
     436. Uncompensated transimpedance amplifier talks about compensating transimpedance amplifiers—something I’ve not been covering in the course, but might add to the book.
     437. Changing the loudspeaker lab talks about changing the loudspeaker lab to use the Analog Discovery 2.  The data measurement will be much quicker now and include phaseinformation, so fitting is trickier and I needed to change the model I fit to.
     438. Analog Discovery 2 oscilloscope input impedance talks about measuring the input impedance of the oscilloscope, and raises a question when I can’t model it consistent with the hardware manual.
     439. Analog Discovery 2 oscilloscope input impedance fixed resolves the problem in the preceding post—I had not remembered to include parasitic capacitances for the reference resistor and the wiring to the scope.
     440. Progress on my book describes the progress I’ve been making this summer on the book and how much it would cost for a paper copy.
     441. Parts and tools list for BME 51A Winter 2018 lists the tools and parts to be included in the student kit paid for by the course lab fee (just for BME 51A, not BME 51B).
     442. Jig for drilling Lego bricks shows the new jig I’ll be using this year for drilling Lego bricks.
     443. Laser cutting electrode holders shows the newly cut electrode holders for 2018.
     444. Book released for Winter 2018 course announced the release of the newest draft of the book, just in time for Winter 2018 courses.
     445. EKG without amplifier is pretty much what it sounds like: recording EKG signals without adding an amplifier, both with the Analog Discovery 2 and with a Teensy LC running PteroDAQ.
     446. Ron vs Vgs for pFETs and nFETS characterizes the MOSFETS I have at home, to try to see which are most suitable for buying for the course in the Spring.
     447. Breakout board for SOT-23 FETs  talks about the design of a half-H-bridge board for using surface-mount FETs in the class-D amplifier lab.
     448. SOT-23 FETs for half H-bridge shows the half-H-bridge boards populated and tested.
     449. Parts and tools list for BME 51B Spring 2018 gives the parts and tools list for the second half of the course (based on the assumption that SOT-23 FETs will be used for the class-D amplifier).
     450. Active Learning Classroom discusses the new space that the labs are being taught in this year.
     451. Starting new quarter talks about lack of correlation between EE101 grades before BME51A and BME 51A grades and about what can be done to improve BME 51B grades over BME 51A grades.
     452. Quiz disappointment talks about a rather disappointing result on the first quiz of the quarter and asks for help.
     453. Rapid delivery tells of fixing a mistake on my parts list with rapid delivery from DigiKey.
     454. Leanpub changing their pricing model again talks about changes to the Leanpub pricing model, which does not affect the Applied Electronics for Bioengineers book, but which would affect decisions to do a new book with Leanpub.
     455. VCO (voltage-controlled oscillator) presents two very similar designs for voltage-controlled oscillators (one that has frequency linear with voltage, and one that is exponential with voltage).
     456. Analog Discovery Impedance Analyzer does a brief review of the new impedance analyzer board.  It seems to work well, and it is a nice addition to my tool set, but is not worth investing in 25 copies of for the course.
     457. Analog Discovery breadboard adapter presents my initial thoughts on using the new Analog Discovery breadboard adapter for the class—it looks useful for lecturing, but not so much for the lab.
     458. Learning outcomes for my electronics course lists the learning outcomes I put on the syllabus for the Applied Electronics for Bioengineers course.
     459. Book progress gives a brief progress report on the book rewrite and asks readers for some guidance on what to do about publishing and marketing.
     460. Redrawing figure in SVG gives the new hand-written SVG for the cross-section of an nFET.
     461. Note that describes recent progress on the book rewrite.
     462. New book cover draft shows a draft of a new cover for the book and mentions recent progress.
     463. New book cover draft 2 shows  yet another draft of a new cover for the book and a new figure for the book (a solder-joint cross-section).
     464. Another book cover design is yet another book cover design—this one a little brighter and less symmetric.
     465. New book cover draft 4 shows a more colorful and cartoony schematic, for a brighter look.
     466. New book cover draft 5 fixes some spacing and size problems with the previous draft.
     467. Progress on editing book reports on progress on the final edit before the fall/winter 2018 release.
     468. New book cover draft 6 is yet another minor tweak to the book cover.
     469. Slow progress on editing book updates the progress report—the global edits are taking longer than expected.
     470. Parts and tools list for BME 51A Winter 2019 lists the parts and tools ordered for the students.
     471. Project Baseline is mainly about a medical study that I’m participating in, but mentions a possibility of using MicroGard II mouthpieces for the breath-pressure lab.
     472. I may be self-publishing forever comments on the difficulty of getting textbooks published.
     473. Textbook on sale announces participation in LeanPub’s holiday sale.
     474. Book is done (for now anyway) announces the 2018 Dec 30 release, which should be the final one for the 2019 BME 51A/B course.
     475. Impedance tokens shows the new boards I designed for making unknown impedances for students to test.
     476. Series-parallel and parallel-series indistinguishable points out that there are really only two 3-component, series-parallel RC circuits: R1+(R2||C2) and C1+(R2||C2).
     477. OpenScope MZ review does a little analysis of the OpenScope MZ—mainly looking at its function generator.
     478. OpenScope MZ review: Bode plot continues the review, concluding that the OpenScope MZ is usable for the course, but not a good deal.
     479. One figure has been giving me grief for a long time talks about the problems I had using pattern-fill in SVG and the work-around I ended up with.
     480. Struggles with Canvas talks about the first day of class in Winter 2019.
     481. More typos than expected describes my surprise at how many typos were left in my textbook at the latest release.
     482. Why do I write? talks about my motivation for creating my textbook and writing this blog.  It also updates the number of book corrections found by my students (the count is up to 170).
     483. Inductive spikes talks about some confusion that resulted from having bypass capacitors on the half-H-bridge boards.
     484. Interaction between bias resistor and active high-pass filter corrects an error I made in grading the preamplifier lab reports.
     485. Gain-bandwidth product describes how I collected data for two new figures for the textbook.
     486. Book progress update gives a brief progress report (excuses really) on the update to the book.
     487. Moved PteroDAQ from BitBucket to GitHub is the last major change for the text book.  I just need to do an overall spelling check and formatting check, which should only take a day or two.
     488. Applied Analog Electronics price increase coming soon announces the upcoming new release of the book, and the associated price increase from $5.99 to $7.99.
     489. $1000 royalties! marks a milestone in my textbook sales.
     490. Book Done! marks the release of Edition 1.0 (2019 Dec 08).
     491. Macos 10.15 Catalina vs PteroDAQ mentions a problem in PteroDAQ induced by Apple’s changes to their USB stack.
     492. Parts and tools list for BME 51A Winter 2020 lists the parts and tools (with approximate prices) ordered for BME 51A.  Because the class enrollment was smaller than expected, and some parts were ordered before the small size was known, the actual per-person price was higher than the listed estimates.
     493. First week of class W2020 describes some of the problems and some of the good points about this year’s class, at least so far.
     494. Parts List BME 51B Spring 2020 has the parts list that I sent to BELS for Spring quarter.
     495. Ending a tough quarter and starting a tougher one discusses some of the problems I have to address in teaching the course this year because of the grad-student strike and the COVID-19  restrictions.
     496. Grading done expresses my relief at finishing grading for the year and outlines an experiment I should do associated with the last lab.
     497. Screaming op amp has a graphic I drew for the Museum of Art and History’s drawing activity.
     498. Lowering price of textbook announces a price reduction during the COVID-19 crisis.
     499. Day off today, planning sabbatical discusses some thoughts I have on preparing video tutorials for the book.
     500. First video for electronics book talks about (and links to) the first video I created for the book—§28.1 on inductors.
     501. Transmission lines talks about a subject not covered in the book or course.
     502. Speed of signals in transmission lines continues the previous post, using its result on how the input impedance of a transmission line with a short-circuit or open-circuit load can be used to compute the speed of signal propagation in the transmission line.
     503. Second video for electronics book is my second video—on computing inductance from shape—§28.2.
     504. Third video for electronics book is on Bode plots for inductors—§28.3.
     505. Fourth video for electronics book is on combining an inductor with a capacitor—§28.4.
     506. Fifth video for electronics book completes Chapter 28, giving the impedance for series and parallel RLC circuits (not currently in Chapter 28).
     507. Sixth video for electronics book is on impedance spectroscopy (Chapter 30, Lab 8).
     508. Seventh video for electronics book is on how loudspeakers work §29.1.
     509. Eighth video for electronics book is on nonlinear impedances, needed for modelling loudspeakers, from §29.2.
     510. Ninth video for electronics book is on models for loudspeakers, from §29.2.1.
     511. Compensation in impedance analyzer discusses what I think open-circuit and short-circuit compensation in the Analog Discovery 2 impedance analyzer do.
     512. Tenth video for electronics book does the model fitting for the data in the ninth video.  The data and the fitting techniques are somewhat different from those in the book.
     513. Resonance for non-linear impedance talks about getting resonances with a pair of non-linear impedances.
     514. Error in video points out a small (unimportant) error in the video referred to in Tenth video for electronics book, based on the math in Resonance for non-linear impedance.
     515. Eleventh video for electronics book moves back a little in the book, to show how to do DC characterization of an electret mic.
     516. Twelfth video for electronics book introduces soldering SOT-23 FETs onto a breakout board.
     517. Ring light for iMac describes a failed attempt to improve the chroma keying in OBS by making and using a ring light.
     518. Twenty-one videos for electronics book updates my blog readers on the progress on creating videos.
     519. Fall 2020 plans and tools lists some of my plans and the tools I’ll be using for teaching online in the Fall.
     520. Videos for Fall done! gives a progress report on the creation of mini-lecture videos for the course.
     521. PteroDAQ installation video announces the video for the installation instructions for PteroDAQ.
     522. Parts and Tools BME 51B Fall 2020 lists the parts for the first at-home lab offering of BME 51B.
     523. Last to-do note in book cleared is a progress report on the latest edition of the book, with a plea for help finding URL checkers for PDF files.
     524. Checked URLs in book describes the process I used for checking all the URLs in the PDF files.  I ended up writing my own checker.
     525. Checked tandem-duplicate words in book gives the code I used for looking for tandem duplicate words in both the LaTeX files and the pdf file.
     526. Edition 1.1 released today! The title says it all.
     527. First Zoom lab went ok.
     528. Caught up on grading marks almost the end of BME 51B in Fall 2020.
     529. BME 51A W2021 parts and tools has the new parts list for BME 51A for Winter 2021.
     530. One week into new quarter reports on status in the first weekend of the Winter 2021 quarter, which has at-home labs for BME 51A.
     531. Resonance with nonlinear impedances gives the math for a new section I’ll be adding to the book.  It is a simpler analysis than an earlier post: Resonance for non-linear impedance, but it uses a somewhat less intuitive definition of “resonance” (real-valued impedance, rather than minimum magnitude).
     532. Controlling current presents a simple op-amp circuit for getting small controlled currents.
     533. Last to-do note in book done marks a milestone in getting the latest edition of the book done.
     534. Checked URLs in book marks another milestone.
     535. Edition 1.3 released today! I think that this is the last major release of the book, unless some other instructor decides to offer the course and gives me lots of feedback about desired improvements. 
     536. PVC: Premature Ventricular Contraction discusses a genuine use of the EKG circuit I built.
     537. Contract signed with publisher! says just what the title says—I’ve signed a contract with a publisher to put out paper versions of my textbook.
     538. PVC and pulse looks at the premature ventricular contractions again—this time combined with optical pulse measurements to see whether the PVCs pump blood.
     539. Help needed with writing blurb I need to write a blurb for the textbook, but I’m having difficulty doing so.
     540. Microphone test box is the first post on a test fixture I’m making for playing with sound measurements.
     541. Which cover? asks for advice on the design of the book cover.
     542. Test box resonances continues the saga of the microphone test box.
     543. Book scheduled to come out in June announces the web page where hard copies of my book will be for sale.
     544. PVC again is a repeat look at my PVCs while resting—I plan to monitor my heart using the ECG every few months.  I tried looking at my ECG while exercising, but the results were poor.
     545. No PVC while exercising is my first real attempt at getting my ECG while exercising, using an amplifier with a lower gain and less chance of clipping the signal during movement artifacts. It showed that aerobic exercise suppressed the PVCs.
     546. Lower PVC frequency reported on an apparent drop in my PVC burden.
     547. Better heartbeat detection looked at two algorithms for determining the pulse rate from the EKG signal.
     548. Press release for my book gives a pointer to a press release for the World Scientific Publishing version of the book (as well as 2 covers—theirs, and the one I’ll continue to use for LeanPub sales).
     549. ECG: 2-electrode vs. 3-electrode compares 2-electrode and 3-electrode conformations using the same instrumentation amplifier.
     550. Proofreading my book talks about some of the hassle of proofreading the book.
     551. Milestone: $2k marks my earning $2k in royalties.
     552. Book printed! marks my receiving the first 4 author copies of the book.
     553. Amazon site live! marks Amazon’s web site for the book going live on 19 June 2023, though the official launch date is 6 August 2023, so it is still a pre-order site.
     554. Analog Discovery 2 price reduction relays Digilent’s announcement of a price reduction for the Analog Discovery 2.
     555. PteroDAQ needs new platform talks about the discontinuation of the main platforms for PteroDAQ.
     556. World Scientific is marketing my book points to the flyer that World Scientific is distributing that features my book.