Observe a moment of silence today while the tubes in your scope warm up.
12 June 2016
14 April 1948 -- 12 June 2011
We miss you, Jim.
Observe a moment of silence today while the tubes in your scope warm up.
Observe a moment of silence today while the tubes in your scope warm up.
10 June 2016
A Bibliography of Jim Williams
I've been meaning to update the compiled bibliography of Jim's publications for a while now. I need to do more work on it, but in the meantime, here is a link to the latest version. In 2009, Jim told me that
he had over 350 publications; so far, I've found 319.
The bibliography can be found at http://web.mit.edu/klund/www/jw/jwbib.pdf.
The bibliography can be found at http://web.mit.edu/klund/www/jw/jwbib.pdf.
Five Years
Paul Rako has written a new remembrance of Jim at EDN. It's hard to believe that this weekend marks the fifth anniversary of his death.
28 October 2014
Some History of Bandgap References
I am finally giving this talk on the East Coast in an open-to-the-public venue. It's not about Jim Williams, but it does mention Bob Widlar (and [spoiler] it includes my favorite Bob Widlar story). If you're in the neighborhood, please come!
Abstract:
Bob Widlar designed the first commercial bandgap voltage reference and introduced it with an elaborate ruse in 1969. The National Semiconductor LM109 was more than a simple reference, it was a feature-packed integrated circuit that jump-started the category of three-terminal voltage regulators. Over the next few years, the LM109 was followed up by the National LM113 current shunt, the LM199 temperature-controlled buried zener, and ground-breaking products from Analog Devices, Precision Monolithics, Linear Technology, and others. This talk discusses the history and design of voltage regulators, references, and current sources from the 1960s to present day.
Some History of Bandgap References
Electrical Engineering Seminar Series
Harvard School of Engineering and Applied Sciences
3pm, Friday, 31 October 2014
Maxwell Dworkin G125
Electrical Engineering Seminar Series
Harvard School of Engineering and Applied Sciences
3pm, Friday, 31 October 2014
Maxwell Dworkin G125
Abstract:
Bob Widlar designed the first commercial bandgap voltage reference and introduced it with an elaborate ruse in 1969. The National Semiconductor LM109 was more than a simple reference, it was a feature-packed integrated circuit that jump-started the category of three-terminal voltage regulators. Over the next few years, the LM109 was followed up by the National LM113 current shunt, the LM199 temperature-controlled buried zener, and ground-breaking products from Analog Devices, Precision Monolithics, Linear Technology, and others. This talk discusses the history and design of voltage regulators, references, and current sources from the 1960s to present day.
12 January 2014
James K. Roberge
Another giant of analog circuit design has left us: It is with great sadness that I report that James K. Roberge passed away on Friday.
A short obituary from the Boston Globe is here.
Professor Roberge and I taught MIT 6.331 "Advanced Circuit Techniques" together this past term (Roberge describes this course in "Propagation of the Race (of Analog Circuit Designers)", Chapter 10 of Jim Williams's first book). Here's a picture that I snapped of him during the last lecture on December 11, 2013. I'm sorry for the terrible cell-phone quality, but I didn't know it'd be the last time I'd see him. He was born to teach, he was happiest when teaching, and this is how I'll remember him (teaching circuits, and here, discussing the Pade approximate for a time delay in active filter design).
I'm at a loss for words.
Update. Two more (better) pictures of Professor Roberge: Here's a photo from earlier in the Fall term of 6.331 (late October) where he was discussing voltage-reference circuits, and the calibration thereof (photo courtesy of Zhen Li).
Here's a photo from the end of the Spring term, of his famous "Train Lecture" in 6.302, where he uses the speed control of a model train (a Lionel O-gauge engine, his favorite) as a vehicle to discuss motor instrumentation, phase-lock loops, and feedback compensation (photo courtesy of Prof. David Trumper).
I had a work-related conversation with a friend and colleague last night, and I said, "I wish I could ask Jim" only three times.
A short obituary from the Boston Globe is here.
Professor Roberge and I taught MIT 6.331 "Advanced Circuit Techniques" together this past term (Roberge describes this course in "Propagation of the Race (of Analog Circuit Designers)", Chapter 10 of Jim Williams's first book). Here's a picture that I snapped of him during the last lecture on December 11, 2013. I'm sorry for the terrible cell-phone quality, but I didn't know it'd be the last time I'd see him. He was born to teach, he was happiest when teaching, and this is how I'll remember him (teaching circuits, and here, discussing the Pade approximate for a time delay in active filter design).
I'm at a loss for words.
Update. Two more (better) pictures of Professor Roberge: Here's a photo from earlier in the Fall term of 6.331 (late October) where he was discussing voltage-reference circuits, and the calibration thereof (photo courtesy of Zhen Li).
Here's a photo from the end of the Spring term, of his famous "Train Lecture" in 6.302, where he uses the speed control of a model train (a Lionel O-gauge engine, his favorite) as a vehicle to discuss motor instrumentation, phase-lock loops, and feedback compensation (photo courtesy of Prof. David Trumper).
I had a work-related conversation with a friend and colleague last night, and I said, "I wish I could ask Jim" only three times.
06 January 2014
The History of "Analog", part 1
When did the word "analog" obtain its present meaning?
I've been researching some topics in the history of electronics, and as I was digging around, it crossed my mind that the word "analog" has an interesting history itself. Its definition and use changed several times during the twentieth century. In the 1989 print edition of the Oxford English Dictionary, the only engineering use of the word analog (of course, they spelt it "analogue") was as an adjective before the word "computer":
So, when did the meaning of "analog" change from "scale model" to its modern definition? I plan to find out. One interesting way to trace the evolution of the word is to find when it became commonly accepted enough to appear in the titles of publications, rather than in the text, where its meaning could be easily defined with a footnote or parenthetical phrase(2).
I've been digging around a little bit, and I've found some interesting things, and about which I have many comments, which I will share over the next few posts.
Spoilers:
Can't wait? Here are some early findings: The first published articles to use the word "analog" (as a noun) in the title were a pair of papers by H. H. Skilling of Stanford University in 1931:
Footnotes:
I've been researching some topics in the history of electronics, and as I was digging around, it crossed my mind that the word "analog" has an interesting history itself. Its definition and use changed several times during the twentieth century. In the 1989 print edition of the Oxford English Dictionary, the only engineering use of the word analog (of course, they spelt it "analogue") was as an adjective before the word "computer":
ANALOGUE --- (adjective) analogue computer, a computer which operates with numbers represented by some physically measurable quantity, such as weight, length, voltage, etc.The 2013 on-line edition has a much improved and expanded entry for the word, which includes
ANALOGUE --- (adjective) typically contrasted with digital... 1c. of signals or data: represented by a continuously variable physical quantity, such as voltage, spatial position, etc.However, in the context of circuit design and signal processing, I prefer the definition
ANALOG --- (adjective) in signals, continuous in amplitude and time; in circuit design, circuits that operate on these signals using continuous quantitiesas opposed to
DIGITAL --- (adjective) in signals, quantized in amplitude and discrete in time; in circuit design, circuits that operate on discrete-time signals using quantized (usually binary) representations.I don't insist these definitions are exhaustive or complete(1), but they draw a line in the sand for the starting point in this archaeological dig.
So, when did the meaning of "analog" change from "scale model" to its modern definition? I plan to find out. One interesting way to trace the evolution of the word is to find when it became commonly accepted enough to appear in the titles of publications, rather than in the text, where its meaning could be easily defined with a footnote or parenthetical phrase(2).
I've been digging around a little bit, and I've found some interesting things, and about which I have many comments, which I will share over the next few posts.
Spoilers:
Can't wait? Here are some early findings: The first published articles to use the word "analog" (as a noun) in the title were a pair of papers by H. H. Skilling of Stanford University in 1931:
[1] H. H. Skilling, "An electric analog of friction for solution of mechanical systems such as the torsional-vibration damper," Transactions of the American Institute of Electrical Engineers, vol. 50, no. 3, pp. 1155-1158, Sep. 1931.The first published article to use the word "analog" as an adjective in the title was published in 1948:
[2] H. H. Skilling, "Electric analogs for diffi cult problems," Electrical Engineering, vol. 50, no. 11, pp. 862-865, Nov. 1931.
[3] E. L. Harder and G. D. McCann, "A large-scale general-purpose electric analog computer," Transactions of the American Institute of Electrical Engineers, vol. 67, no. 1, pp. 664-673, Jan. 1948.The first book(3) to use the word "analog" in the title was the classic text by Korn and Korn in 1952:
[4] Granino A. Korn and Theresa M. Korn, Electronic Analog Computers. New York: McGraw-Hill, 1952.Analog Devices, Inc. was founded in 1965, see:
[5] Walt Jung, "Op amp history," in Op Amp Applications, Walter G. Jung, Ed. Norwood, Mass.: Analog Devices, 2002, ch. H, p. H.35.The first books to use the words "analog" and "circuit" in the title were published in 1972:
[6] Dan Sheingold, "Editor's notes: Analog dialectic," Analog Dialogue, vol. 30, no. 3, p. 1, 1996.
[7] Alan B. Grebene, Analog Integrated Circuit Design. New York: Van Nostrand Reinhold, 1972.If you have additional (or contradictory!) information, please leave a comment.
[8] Jacob Millman and Christos C. Halkias, Integrated Electronics: Analog and Digital Circuits and Systems. New York: McGraw-Hill, 1972.
Footnotes:
- For example, switched-capacitor filters are continuous in amplitude and discrete in time, and asynchronous digital systems do exist.
- This approach has the added bonus of being easier to research, given modern searchable databases, so it makes a good starting point (but just a starting point).
- I define "book" to mean published by a major publishing house for public distribution. Technical reports, computer manuals, and theses don't count.
01 January 2014
Top Five Posts 2013
A year ago, I declared the "Top Five Most Popular Posts in 2012". A year before that, I declared the "Top Five Most Popular Posts in 2011" with an incomplete year of data. Therefore, following the tradition, I do declare:
The Top Five Most Popular Posts in 2013
Some of the stats don't make sense (part two above part one?), so I suspect that Blogger suffered some kind of soft reset sometime during the year. Nonetheless, I charge forward with the only data I have. Also, I note that all of these posts are from 2011 and 2012, which is further evidence of my falling down on the job here. I hope that I will produce more interesting posts in the coming months.
The Top Five Most Popular Posts in 2013
- Best App Notes Page (2012 rank: #1)
- Scope Sunday 13 (2012 rank: #2)
- Vintage Scopes are Better, part 2
- Vintage Scopes are Better, part 1 (2012 rank: #3)
- My Favorite Widlar Story (2012 rank: #6)
Not really a "post" in the strictest sense of the word, but this page received the most traffic in 2012. It continues to be updated as I continue to read...
Photos from my trip to the Computer History Museum to see the opening night of Jim's Linear Technology laboratory bench on display (with my business card in the mess).
The second part of a five-part series. See below for part one.
The first part of my five-part series on why vintage analog oscilloscopes are better than modern digital ones, with plenty of quotes from Jim. See also part two, part three, part four, and part five.
A retelling of the three-terminal-voltage-regulator prank. My second-favorite Bob Widlar story is the one about the sheep.
Some of the stats don't make sense (part two above part one?), so I suspect that Blogger suffered some kind of soft reset sometime during the year. Nonetheless, I charge forward with the only data I have. Also, I note that all of these posts are from 2011 and 2012, which is further evidence of my falling down on the job here. I hope that I will produce more interesting posts in the coming months.
31 December 2013
Just 10
I am embarrassed to realize that this post is only my tenth post for 2013. Thus, a "look back" can be comprehensive AND short. Out of those ten posts, only five contained actual content, and all five were "Scope Sundays":
I promise 2014 will be better... I already have a number of posts planned. (Plus, I still have 10 of Jim's app notes to read!)
- Scope Sunday 42 --- some 500-series plug-ins and a 576.
- Scope Sunday 43 --- new plug-ins, and off to Dayton.
- Scope Sunday 44 --- a 514AD from Craigslist.
- Scope Sunday 45 --- a 661 from eBay.
- Scope Sunday 46 --- help identify a mystery scope?
I promise 2014 will be better... I already have a number of posts planned. (Plus, I still have 10 of Jim's app notes to read!)
20 November 2013
Scope Sunday 46
Our correspondent writes with the following question: Do you recognize this scope?
This photo appears on page 240 of the 1963 MIT yearbook, and appears to be a picture of an undergraduate teaching laboratory. Notable is the method of showing the time and voltage settings. There was a hole in the front panel above the knob and the sensitivity was shown through a back-lit dial. The scope was tan in color with dark brown features.
Footnote: Our initial correspondent is none other than John Addis, who wrote Chapter 14, "Good Engineering and Fast Vertical Amplifiers", in Jim Williams's first book. Bernard Gordon, founder of Analogic Corporation, wrote Chapter 5 in that same book. It's all connected.
This photo appears on page 240 of the 1963 MIT yearbook, and appears to be a picture of an undergraduate teaching laboratory. Notable is the method of showing the time and voltage settings. There was a hole in the front panel above the knob and the sensitivity was shown through a back-lit dial. The scope was tan in color with dark brown features.
Several people have suggested that the brand name was "Analogic", but the present-day Analogic Corporation did not exist until 1967.
Does anybody recognize this scope?
Footnote: Our initial correspondent is none other than John Addis, who wrote Chapter 14, "Good Engineering and Fast Vertical Amplifiers", in Jim Williams's first book. Bernard Gordon, founder of Analogic Corporation, wrote Chapter 5 in that same book. It's all connected.
23 June 2013
Scope Sunday 45
My friend Eugene pointed me to a Tektronix 661 on eBay (it was the first one I'd seen in quite a while). I've wanted this scope for a long time. I even mentioned back in Scope Sunday 2.
Jim mentioned his Tek 661 quite a few times: He used it in App Note 74, and tt is pictured on the back cover. He used it in Figure 77 of App Note 72 and also in App Note 61. I'm excited to have my own, and if it works, I'll have to get to work on building some more high-speed pulse generators.
Jim mentioned his Tek 661 quite a few times: He used it in App Note 74, and tt is pictured on the back cover. He used it in Figure 77 of App Note 72 and also in App Note 61. I'm excited to have my own, and if it works, I'll have to get to work on building some more high-speed pulse generators.
17 June 2013
Scope Sunday 44
I'm a day late with this post, but I did want to report on recent activities. Yesterday, I spent the morning at the MIT Swapfest, but did not purchase anything. Instead, I sold some Hewlett Packard and General Radio manuals and catalogs that I had rescued from the trash at M.I.T. (Next month, I will be selling some similarly diverted Tektronix manuals.) There was a $10 Tektronix 564B, but I'm not really into the 560 series (despite the fact that I own a 3S1 and one 561B). Besides, someone else had bought it before the end of the flea market.
This scope has some interesting features: It was the first scope to offer both a 10-MHz bandwidth and DC response (the 511 only had the former, the 512 only had the latter). The 514AD version include a 24-section 250-ns LC delay line. It also includes (I am told) tons of selenium rectifiers. Fun!
I did buy a scope last week (actually, two, but the second half of this story will come next week): I found a Tektronix 514AD on Craigslist.
This scope has some interesting features: It was the first scope to offer both a 10-MHz bandwidth and DC response (the 511 only had the former, the 512 only had the latter). The 514AD version include a 24-section 250-ns LC delay line. It also includes (I am told) tons of selenium rectifiers. Fun!
12 June 2013
14 April 1948 -- 12 June 2011
We miss you, Jim.
Observe a moment of silence today while the tubes in your scope warm up.
03 June 2013
Some History of Bandgap References
I am giving a talk at Stanford University on Thursday. It's not about Jim Williams, but it does mention Bob Widlar (and it includes my favorite Bob Widlar story [spoiler!]). If you're in the neighborhood, please come!
Abstract:
Prankster Bob Widlar designed the first commercial bandgap voltage reference and introduced it with an elaborate ruse in 1969. The National Semiconductor LM109 was more than a simple reference, it was a feature-packed integrated circuit that jump-started the category of three-terminal voltage regulators. Over the next few years, the LM109 was followed up by the National LM113 current shunt, the LM199 temperature-controlled buried zener, and ground-breaking products from Analog Devices, Precision Monolithics, Linear Technology, and others. This talk discusses the history and design of voltage regulators, references, and current sources from the 1960s to present day.
Some History of Bandgap References
Rethinking Analog Design Seminar
Stanford University Electrical Engineering
4pm, Thursday, 6 June 2013
Allen 101
Rethinking Analog Design Seminar
Stanford University Electrical Engineering
4pm, Thursday, 6 June 2013
Allen 101
Abstract:
Prankster Bob Widlar designed the first commercial bandgap voltage reference and introduced it with an elaborate ruse in 1969. The National Semiconductor LM109 was more than a simple reference, it was a feature-packed integrated circuit that jump-started the category of three-terminal voltage regulators. Over the next few years, the LM109 was followed up by the National LM113 current shunt, the LM199 temperature-controlled buried zener, and ground-breaking products from Analog Devices, Precision Monolithics, Linear Technology, and others. This talk discusses the history and design of voltage regulators, references, and current sources from the 1960s to present day.
12 May 2013
Scope Sunday 43
Once again, I find myself apologizing for a lengthy absence, but this term's teaching obligations got the better of me. I taught three classes this Spring, and that's a schedule that I should remember NOT to repeat. However, I have submitted final grades for two of the classes, and I'm looking forward to getting back to my "other" jobs. In the meantime, here are three scope-related updates:
Both of these plug-ins remind me of Jim. Jim suggested that the 1A7 manual was one of the first examples of the word "cascode" being used to refer to the transistor circuit (I subsequently found an earlier reference). And, of course, the 7M13 is the plug-in that he used to put his "signature" on the cartoon in App Note 94. The cartoon shows off his 7104 scope, "I'm going as fast as I can."
Compare the photo above to the photo below that I took ONE YEAR AGO. Other than better picture quality, not much has changed. I guess there isn't much market for $20 7A18 plug-ins and 7B53 plug-ins.
1. Last weekend, I attended NEAR-fest up in Deerfield, N.H. This year, the weather was beautiful, but the pickings were slim. I did, however, buy two scope plug-ins, 1A7A and a 7M13.
Both of these plug-ins remind me of Jim. Jim suggested that the 1A7 manual was one of the first examples of the word "cascode" being used to refer to the transistor circuit (I subsequently found an earlier reference). And, of course, the 7M13 is the plug-in that he used to put his "signature" on the cartoon in App Note 94. The cartoon shows off his 7104 scope, "I'm going as fast as I can."
2. On the way home from NEAR-fest, I stopped by Electronic Surplus Services in Manchester, but I all found was a shelf of undesirable plug-ins (mostly 7A18 vertical amplifiers and slow time bases).
Compare the photo above to the photo below that I took ONE YEAR AGO. Other than better picture quality, not much has changed. I guess there isn't much market for $20 7A18 plug-ins and 7B53 plug-ins.
3. Next weekend is the Dayton Hamvention. Let me know if you're going; I hope to see you there. Here's a picture I took last year:
23 January 2013
EE Prototyping Redirect
I have previously posted here about the EE Prototyping course that I will be
teaching at Olin College this spring (see
all posts with the label "Prototyping"). While I still believe that Jim
Williams would have loved this class, I have decided to split that
discussion off into its own dedicated blog.
If you'd like to continue to follow the development of "EE Proto" this term, please join my students and me over at eepro.to.
If you'd like to continue to follow the development of "EE Proto" this term, please join my students and me over at eepro.to.
22 January 2013
Scope Sunday 42
A friend emailed me last week, and said that he had some Tektronix 500-series plug-ins for me. I told him that I was happy to give them a good home. When I arrived at his house on Sunday, he had a dozen-and-a-half plug-ins for me, and also this back-breaking beast:
He said that it has a small oscillation problem, and it didn't come with any fixtures, but I am very pleased. I have several 575s (and even a 175 with the special cable), but this treasure is my first 576.
He said that it has a small oscillation problem, and it didn't come with any fixtures, but I am very pleased. I have several 575s (and even a 175 with the special cable), but this treasure is my first 576.
01 January 2013
Top Five Posts 2012
I started this blog in July 2011, so today is the first time I have a year of data for an end-of-year round up. A year ago, I declared the "Top Five Most Popular Posts in 2011" with an incomplete year of data. Therefore, today, with a full year of data, I do declare:
The Top Six Most Popular Posts in 2012
Note that some of these posts are from 2011, but the ranking is based only on their traffic in 2012 (search engines at work). Of course, once again I note that listing these links gives these posts a head start in the race for "Most Popular Posts in 2013" (it's an interesting positive-feedback loop, isn't it?), but I hope that I will produce even more interesting posts in the coming months!
Which post was your favorite?
The Top Six Most Popular Posts in 2012
- Best App Notes Page
- Scope Sunday 13 (2011 rank: #3)
- Vintage Scopes are Better, part 1
- Scope Sunday 23
- Scope Sunday 3 (2011 rank: #1)
- My Favorite Widlar Story
Not really a "post" in the strictest sense of the word, but this page received the most traffic in 2012. It continues to be updated as I continue to read...
Photos from my trip to the Computer History Museum to see the opening night of Jim's Linear Technology laboratory bench on display (with my business card in the mess).
The first part of my five-part series on why vintage analog oscilloscopes are better than modern digital ones, with plenty of quotes from Jim. See also part two, part three, part four, and part five.
Notes and photos from my return trip to the Computer History Museum, where I make note of the large number of Tektronix oscilloscopes in their collection (whether they want to admit it or not!).
My airline adventure with a Tektronix 453, along with a letter from Jim.
A retelling of the three-terminal-voltage-regulator prank. My second-favorite Bob Widlar story is the one about the sheep.
Note that some of these posts are from 2011, but the ranking is based only on their traffic in 2012 (search engines at work). Of course, once again I note that listing these links gives these posts a head start in the race for "Most Popular Posts in 2013" (it's an interesting positive-feedback loop, isn't it?), but I hope that I will produce even more interesting posts in the coming months!
Which post was your favorite?
04 November 2012
Scope Sunday 41
This post is Part Two of my California trip report. Last week I wrote about shopping at Excess Solutions, HSC, and the Pacificon Swap Meet. This week, I finish the story with my experiences at WeirdStuff.
In short, disappointing. I was last at WeirdStuff back in January 2012, where I saw a Tektronix 502 for $160 and a broken 7904 without plug-ins for $250. Both of these scopes were still in stock, at the same prices. The 502 is now missing four knobs.
The broken 7904 ("No power") is still on the shelf as well. I admit that I don't know anything about running a surplus store like WeirdStuff, but if your inventory isn't selling (and it's been a year for the 502, and at least 18 months for the 7904), shouldn't you lower your prices? Wouldn't inventory turnover be more important than waiting for that one buyer who's going to pay top dollar? Especially if people are stealing the knobs in the meantime?
A few other over-priced items also caught my eye. There was a Type D plug-in unit, missing all of its knobs and tubes, for $10. (I might pay $10 for a complete one, but then again, I already have a few of them.)
There was a Tektronix 529 TV Waveform Monitor (also missing a few knobs) for $100. Way too much (the $30 price tag was for the cart, not the monitor).
Seriously, though, I hope that they catch the degenerate low-life that's stealing all the knobs off these scopes and pull out his fingernails. Slowly.
I'll close here with a last picture from the Pacificon Swap Meet. Instead of paying $250 for a broken 7904 without plug-ins at WeirdStuff, you could have bought a working 7904 with plug-ins and cart at the Swap Meet for $300. I still think this price is too much, but only by a factor of two, instead of a factor of ten!
In short, disappointing. I was last at WeirdStuff back in January 2012, where I saw a Tektronix 502 for $160 and a broken 7904 without plug-ins for $250. Both of these scopes were still in stock, at the same prices. The 502 is now missing four knobs.
The broken 7904 ("No power") is still on the shelf as well. I admit that I don't know anything about running a surplus store like WeirdStuff, but if your inventory isn't selling (and it's been a year for the 502, and at least 18 months for the 7904), shouldn't you lower your prices? Wouldn't inventory turnover be more important than waiting for that one buyer who's going to pay top dollar? Especially if people are stealing the knobs in the meantime?
A few other over-priced items also caught my eye. There was a Type D plug-in unit, missing all of its knobs and tubes, for $10. (I might pay $10 for a complete one, but then again, I already have a few of them.)
There was a Tektronix 529 TV Waveform Monitor (also missing a few knobs) for $100. Way too much (the $30 price tag was for the cart, not the monitor).
Seriously, though, I hope that they catch the degenerate low-life that's stealing all the knobs off these scopes and pull out his fingernails. Slowly.
I'll close here with a last picture from the Pacificon Swap Meet. Instead of paying $250 for a broken 7904 without plug-ins at WeirdStuff, you could have bought a working 7904 with plug-ins and cart at the Swap Meet for $300. I still think this price is too much, but only by a factor of two, instead of a factor of ten!
28 October 2012
Scope Sunday 40
Two weeks ago (second weekend in October), I was in California, and I scheduled some time to do some junk shopping. I stopped by some of the surplus stores that Jim introduced me to, including Excess Solutions in Milpitas, Weirdstuff in Sunnyvale, and HSC in Santa Clara.
In addition to some surplus junk, Excess Solutions has rows and rows of components. I bought some of the capacitors that I used in my Capacitor Quiz last week.
I also stopped at HSC Electronic Supply, where they have a new banner sign with an unnecessary apostrophe.
They did have some interesting Tektronix hardware, but most of it was too rich for my blood, like this Type G plug-in unit, which was missing all its knobs and tubes, priced at $25.
However, this 3S1 dual-trace sampler was just too good to resist. It seems to be complete, but there were at least two broken components on the B channel (the vertical-position pot and a trimmer capacitor near the sampling bridge, C433). I don't actually have any 560-series mainframes (well, I have one), but I couldn't pass it up. Due to the damage, I talked the manager down to $25, and packed it into my carry-on bag for the flight home.
Saturday morning (being the second Saturday of the month) should have been the Electronics Flea Market at De Anza, but it was canceled due to a conflict with Pacificon. However, there was a swap meet scheduled for Saturday morning at Pacificon, so I went to that. It was hopping well before dawn (unfortunately I didn't have a flashlight). Here's a picture I took while it was still pitch black out.
There was some nice Tektronix gear there, including a rack-mount 545B, a nice 465B, some 7000 gear, and this 491 spectrum analyzer.
Of course, The Fates taunted me. Having just bought the 3S1 last night, I was tempted by a whole lot of 560-series equipment, including three 561 mainframes, 17 assorted plug-in units, and a cart. Of course, there was no way to get it home, or arrange to get it home (my plane departed a few hours later, early that afternoon), and I am confident that I can find these scopes closer to home. Still, funny.
Eagle-eyed observers will notice a pristine copy of Stan Griffiths' book, Oscilloscopes: Selecting and Restoring a Classic, on top of the 561B. Unfortunately, the seller would not sell it alone; it was part of the whole giant 560-series package (which was wise). You can buy a scan of it from the VintageTEK museum store. I hope somebody bought the whole lot of scopes (I probably would have, if it wasn't 3000 miles from home).
The trip home was uneventful. I carried the 3S1 sampler in my carry-on briefcase, but I had no problems at the airport. The TSA agents did test it for explosive residue, but they didn't even ask me what it was. Having breezed through security, I really regret not buying the 465B scope that I saw.
In addition to some surplus junk, Excess Solutions has rows and rows of components. I bought some of the capacitors that I used in my Capacitor Quiz last week.
I also stopped at HSC Electronic Supply, where they have a new banner sign with an unnecessary apostrophe.
They did have some interesting Tektronix hardware, but most of it was too rich for my blood, like this Type G plug-in unit, which was missing all its knobs and tubes, priced at $25.
However, this 3S1 dual-trace sampler was just too good to resist. It seems to be complete, but there were at least two broken components on the B channel (the vertical-position pot and a trimmer capacitor near the sampling bridge, C433). I don't actually have any 560-series mainframes (well, I have one), but I couldn't pass it up. Due to the damage, I talked the manager down to $25, and packed it into my carry-on bag for the flight home.
Saturday morning (being the second Saturday of the month) should have been the Electronics Flea Market at De Anza, but it was canceled due to a conflict with Pacificon. However, there was a swap meet scheduled for Saturday morning at Pacificon, so I went to that. It was hopping well before dawn (unfortunately I didn't have a flashlight). Here's a picture I took while it was still pitch black out.
There was some nice Tektronix gear there, including a rack-mount 545B, a nice 465B, some 7000 gear, and this 491 spectrum analyzer.
Of course, The Fates taunted me. Having just bought the 3S1 last night, I was tempted by a whole lot of 560-series equipment, including three 561 mainframes, 17 assorted plug-in units, and a cart. Of course, there was no way to get it home, or arrange to get it home (my plane departed a few hours later, early that afternoon), and I am confident that I can find these scopes closer to home. Still, funny.
Eagle-eyed observers will notice a pristine copy of Stan Griffiths' book, Oscilloscopes: Selecting and Restoring a Classic, on top of the 561B. Unfortunately, the seller would not sell it alone; it was part of the whole giant 560-series package (which was wise). You can buy a scan of it from the VintageTEK museum store. I hope somebody bought the whole lot of scopes (I probably would have, if it wasn't 3000 miles from home).
The trip home was uneventful. I carried the 3S1 sampler in my carry-on briefcase, but I had no problems at the airport. The TSA agents did test it for explosive residue, but they didn't even ask me what it was. Having breezed through security, I really regret not buying the 465B scope that I saw.
26 October 2012
EE Prototyping 4
Design of the "EE Prototyping" course moves steadily forward. Unfortunately, there hasn't been a lot to blog about because the topics we've been discussing have been mostly formalities:
We've also been brainstorming about lecture topics for a few weeks. Some of the suggested topics include:
The seminar did work on a little class project that I'll talk about next week, but here's a hint:
The reading assignment last week was two chapters in Jim Williams' 1995 book: Chapter 1, "The importance of fixing" (that's another hint!) and Chapter 17, "There's no place like home". This week, the reading assignment is to start reading Bob Pease's book, Troubleshooting Analog Circuits.
- How often should the course meet? Twice a week? Three times a week? What is the balance between lecture time and laboratory time for this course? Should we use afternoon lectures and evening labs (like some other courses at Olin)? How long should the class/lab sessions be?
- Should the course satisfy "Graduation Requirement A" or "Graduation Requirement B" or both? What are the necessary attributes of a course that satisfies "Graduation Requirement B"?
- What topics should be covered in lecture?
- How should the reading assignments be ordered and structured?
We've also been brainstorming about lecture topics for a few weeks. Some of the suggested topics include:
- Schematic dos and don'ts
- Grounding: analog versus digital, ground planes, stars, and the chassis
- What's so special about 50 ohms?
- Noise and non-noise
- Proper use of oscilloscopes and probes
- Op-amp applications and nonidealities
- Care and feeding of A/D converters
- The wonderful (horrible) world of capacitors
- Heat sinks and thermal problems
- Power supply design
The seminar did work on a little class project that I'll talk about next week, but here's a hint:
The reading assignment last week was two chapters in Jim Williams' 1995 book: Chapter 1, "The importance of fixing" (that's another hint!) and Chapter 17, "There's no place like home". This week, the reading assignment is to start reading Bob Pease's book, Troubleshooting Analog Circuits.
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