max@zion.berkeley.edu (Max Hauser) (08/02/87)
Catching up on sci.electronics recently I enjoyed reading all the
postings about magic-eye tubes, magamps, etc. By coincidence,
I recently put together an old-farts' electronics quiz and
circulated it locally. A copy is attached for your amusement.
Questions 12 and 13 are especially coincidental.
I should explain that the quiz is about general, pre-microprocessor
electronics -- 1960's technology, roughly. Mostly solid-state,
a little RF, a little "analog", a little "digital", and some
industrial trivia. Engineers here have been taking it and
predictably, the ones who were working or at least hacking 15-20
years ago know the answers. Even more notable, though, it is usual
for recent EE graduates to be mystified by *all* of the questions.
I hope this evokes some nostalgia; it's strictly for fun.
(As for actually being an old fart -- well, I was I was born
in 1956, and I remember this stuff -- does that make me one?)
Max Hauser, UC Berkeley EECS Department
UUCP: ...{!decvax}!ucbvax!eros!max
Internet (old style): max%eros@berkeley
Internet (domain style): max@eros.berkeley.edu
Questions to identify old-fart electronics hackers. (General,
pre-microprocessor electronics.)
(No fair looking it up.)
1. Assuming that you are acquainted with the "cascode" configuration,
do you know where the term came from?
2. What is a reflex amplifier?
3. What is the basic principle of a superhet receiver? of a regenerative
receiver? The difference between a mixer and a converter (in RF)?
4. Who developed the op amp, and when?
5. What is the "purple plague"?
6. What is a class-C amplifier and where is it typically used?
7. Can you describe a tunnel diode? a unijunction transistor? an SCS?
(What is the basic principle of each and what are they used for.)
8. Traditional op-amp ICs were designed whenever possible to run
on +- 15 volts. Why that voltage?
9. What do the following acronyms stand for: PDP, VAX, ASCII, EBCDIC,
PRV, BFO, RTTY, CW, VSB, VOR, Conelrad?
10. What was revolutionary about the 741 op amp?
11. Can you specifically describe the commercial semiconductor devices
known by the following terms: 1N34, CK722, 2N107, 2N998, 2N1304, 2N2222,
2N3055, U222, uL900, uL958, uA703, uA709, SN7300 series, SUHL, CCSL,
HTL, ECCSL, Utilogic, COSMOS, Intel 1101, Intel 1702.
12. Can you identify the following trademarks: Nixie, Pixie, Numitron?
13. What is a thyratron? a magic-eye tube? a compactron?
14. What magnitudes of voltage(s) are required for operating the
following devices: neon bulb; Xenon flashtube; Geiger-Mueller tube?
15. What IF frequencies are commonly used in the US for AM broadcast,
FM broadcast, TV sound, TV picture?
16. What is a Hartly oscillator? a Colpitts oscillator? a Pierce
oscillator? a Wien-bridge oscillator? a blocking oscillator?
17. What voltage corresponds to zero dBm in a 600-ohm circuit?
(Quick, without calculating).
18. What is an Eccles-Jordan circuit? a polyflop? a switch-tail ring
counter? a Johnson counter? an AC-coupled flip-flop?
19. In the context of filters, what is a biquad? [Note: most engineers
get this wrong.]
20. What does it mean when a resistor is marked with bands
red-yellow-green-silver? a capacitor with letters "104K"?
21. If an aluminum electrolytic capacitor is rated for a "working
voltage" of 10 volts, in what range of voltages is it designed to
operate?
22. Roughly, what are the main advantages and disadvantages of the
following capacitor dielectrics: ceramic, polystyrene, polycarbonate?
23. What is a "2 1/2 D" core memory plane?
24. What is a couplate? a micromodule? the difference between
thin-film and thick-film hybrid circuits?
25. Do you remember the commotion caused by Ovonic devices in 1969?
26. (Practical commercial engineering experience) Can you explain
the following business acronyms: FOB, CIF, NRE, ASP.larry@kitty.UUCP (Larry Lippman) (08/02/87)
In article <19929@ucbvax.BERKELEY.EDU>, max@zion.berkeley.edu (Max Hauser) writes: > Catching up on sci.electronics recently I enjoyed reading all the > postings about magic-eye tubes, magamps, etc. By coincidence, > I recently put together an old-farts' electronics quiz and > circulated it locally. A copy is attached for your amusement. > 5. What is the "purple plague"? Undoubtedly the best question! Ain't no way that anyone other than an old fart will know the answer to this one! And you certainly won't find the answer in any book! > 11. Can you specifically describe the commercial semiconductor devices > known by the following terms: 1N34, CK722, 2N107, 2N998, 2N1304, 2N2222, > 2N3055, U222, uL900, uL958, uA703, uA709, SN7300 series, SUHL, CCSL, > HTL, ECCSL, Utilogic, COSMOS, Intel 1101, Intel 1702. You forgot the 2N35 (probably the first, most common germanium PNP signal transistor) and the 2N255 (a very early and popular germanium PNP power transistor in TO-3 package). I'll never forget the first transistor audio amplifier I built around 1961 using 2N35's; I was truly _amazed_ that it exhibited gain above 100 kHz! The U222 FET from Siliconix was a truly amazing transistor. In a project which I did around 1970, I could get several hundred mW of RF in the VHF frequency region using just one of these devices. > 13. What is a thyratron? a magic-eye tube? a compactron? Don't forget the ignitron, skiatron, and carcinotron (probably the most unusual name for a vacuum tube)... And the T-1 envelope wire-lead subminiature vacuum tube, like the 5647. And "loctal" tubes, "doorknob" tubes, "lighthouse" tubes and "acorn" tubes... > 24. What is a couplate? a micromodule? the difference between > thin-film and thick-film hybrid circuits? Don't forget "cordwood stacking"... <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
max@zion.berkeley.edu (Max Hauser) (08/02/87)
As expected, Larry here put my quiz to shame. In article <1901@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes: > > You forgot the 2N35 (probably the first, most common germanium PNP >signal transistor) and the 2N255 (a very early and popular germanium PNP >power transistor in TO-3 package). Well, actually I didn't forget them, but one has to draw the line somewhere. I still have a box of 2N255s somewhere in storage. They burnt out easily, as I remember... >> 13. What is a thyratron? a magic-eye tube? a compactron? > > Don't forget the ignitron, skiatron, and carcinotron (probably >the most unusual name for a vacuum tube)... I omitted the ignitron on purpose, since it is not all that archaic (it's still heavily used, in power work), but I have never heard of the others! I did warn that it was mostly a solid-state quiz. >> 24. What is a couplate? a micromodule? the difference between >> thin-film and thick-film hybrid circuits? > > Don't forget "cordwood stacking"... Good point, that was a serious omission. What age does to the memory... One more thing -- some people collect old radios; I collect old op amps. I have mint Philbrick K2 series amps going back to the mid-1950s, with Airpax choppers and 12AX7s. Sometimes I give a talk on op-amp evolution to EECS undergrads. I use FETs in the tube schematics for clarity, of course, but you should see the eyes pop at the sight of +- 300V DC power rails. Max Hauser, UC Berkeley EECS Department UUCP: ...{!decvax}!ucbvax!eros!max Internet (old style): max%eros@berkeley Internet (domain style): max@eros.berkeley.edu
larry@kitty.UUCP (Larry Lippman) (08/02/87)
In article <19930@ucbvax.BERKELEY.EDU>, max@zion.berkeley.edu (Max Hauser) writes: > > Don't forget the ignitron, skiatron, and carcinotron (probably > >the most unusual name for a vacuum tube)... > > I omitted the ignitron on purpose, since it is not all that archaic > (it's still heavily used, in power work), but I have never > heard of the others! I did warn that it was mostly a solid-state quiz. The skiatron was an interesting type of CRT which was developed during WW II for projection of radar displays. I believe it was subsequently used for early projection television applications. What is so interesting about the skiatron is that it is a DARK trace tube; the excited area appears as dark magenta against a white background. In practice, bright light from a mercury arc lamp is focused against the front of the tube through a hole in the center of a spherical mirror. The light from the surface image is reflected by the spherical mirror through a Schmidt correcting plate onto a front-surface mirror, and then to a ground-glass image plane. The skiatron was electromagnetically deflected. The carcinotron was the first name given to the BWO (Backward Wave Oscillator) tube. I believe "carcinotron" may have started out as a tradename, but I am not certain. It certainly is a bizarre name for a microwave oscillator tube! Perhaps someone realized that extensive exposure to its output could cause carcinoma :-). BWO's are interesting microwave oscillators since they can be designed to provide output frequencies as high as 500 GHz - that's a pretty short wavelength! BWO's also have an unusually great electrical tuning range - on the order of 2:1. BWO's also ain't cheap; I have an H-P (i.e., High-Priced :-) ) microwave sweep oscillator in my lab with a sick BWO, and H-P wants a mere $ 4K for a replacement BWO... > One more thing -- some people collect old radios; I collect old op > amps. I have mint Philbrick K2 series amps going back to the > mid-1950s, with Airpax choppers and 12AX7s. Sometimes I give a talk > on op-amp evolution to EECS undergrads. I use FETs in the tube > schematics for clarity, of course, but you should see the eyes > pop at the sight of +- 300V DC power rails. There were also some unusual "chopper" circuits which used neon lamps shining against CdS photoresistive cells to provide a non-mechanical means of commutation. Until the instrument world became truly comfortable with solid-state electronics, there were some strange hybrid amplifiers which used various combinations of tubes, transistors and choppers in the same circuit. One of the most complex and difficult to understand/troubleshoot circuits I have ever seen was used by Cary Instruments in their Model 14 spectrophotometer; not only did they combine vacuum tubes, nuvistors, and transistors in the same circuit, but some of the transistors were FET's! I once spent 4 solid days trying to repair one of these gadgets, only to discover that the problem was an open 100 megohm resistor in a nuvistor preamp; who would ever believe that a 100 megohm resistor would be open? And then there was Beckman Instruments, who used solid-state amplifiers with electromagnetic choppers in their Model R Dynagraph instrument recorders and systems. Except that 60 Hz choppers weren't good enough; they used 400 Hz choppers, and even provided a solid-state 400 Hz power supply just to provide excitation current for the choppers! One thing that never seemed to really catch on (except in the telephone industry) was the use of "Fetrons", which were solid-state pin-for-pin replacements for vacuum tubes. Fetrons primarily used FET's. <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
rbl@nitrex.UUCP ( Dr. Robin Lake ) (08/04/87)
In article <19930@ucbvax.BERKELEY.EDU> max@eros.berkeley.edu (Max Hauser) writes: >As expected, Larry here put my quiz to shame. > >In article <1901@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes: >> >> You forgot the 2N35 (probably the first, most common germanium PNP >>signal transistor) and the 2N255 (a very early and popular germanium PNP >>power transistor in TO-3 package). > >Well, actually I didn't forget them, but one has to draw the line >somewhere. I still have a box of 2N255s somewhere in storage. >They burnt out easily, as I remember... > How many netters still have the devices mentioned in their parts box? My parts box was purchased at the ORGINAL Radio Shack store on Washington St. in Boston (now somewhere under City Hall) 31 years ago. Little changed since then, I can find at least 10 of the named devices well- organized in the little drawers! Anyone requiring circuits for these well-aged devices, let me know, for I also saved the early transistor circuit guidebooks from Raytheon, CBS (2N255) and other long-gone manufacturers. P.S. Does anyone have an "01A" vacuum tube? I need one for a vintage vacuum-tube voltmeter. Rob Lake decvax!cwruecmp!nitrex!rbl ihnp4!cbosgd!cwruecmp!nitrex!rbl
robert@uop.UUCP (Glen Fiddich) (08/05/87)
i have been reading and hacking electronics for a long time,
and found that my 1st class license did not get me anything,
except how to answer the old fart quiz...i can't believe
(really i can) someone does not know what a class c amplifier is!
jeezz!!
lets make them really go nuts, and ask them how to build a radio with
a cat whisker and an oatmeal box!!
...sun!ptsfa!cogent! \
...rutgers!retix! --> uop!robert
...seismo!lll-crg!ucdavis! /
the threefold path to the "old fart hall
of cessell elllarry@kitty.UUCP (Larry Lippman) (08/07/87)
In article <504@nitrex.UUCP>, rbl@nitrex.UUCP ( Dr. Robin Lake ) writes: > > I still have a box of 2N255s somewhere in storage. I just looked in my storage building to see if mine were still there. Yup! They were made by Sylvania, have a black top, and the copper is VERY tarnished. > How many netters still have the devices mentioned in their parts box? > My parts box was purchased at the ORGINAL Radio Shack store on Washington > St. in Boston (now somewhere under City Hall) 31 years ago. Little > changed since then, I can find at least 10 of the named devices well- > organized in the little drawers! Anyone remember the "junk" sold by Olson Electronics during the 50's and early 60's? I can recall them selling "modular" vacuum tube assemblies from IBM computers in the early 60's. With some hindsight, this stuff was probably from IBM 709's. Later in the 60's they were selling small IBM printed circuit boards with transistors, probably removed from 1401's and similar early solid-state machines. I don't know if Olson Electronics is still in business; their last store in the Buffalo, NY area closed a few years ago. > P.S. Does anyone have an "01A" vacuum tube? I need one for a vintage > vacuum-tube voltmeter. Vintage VTVM... Lemme guess: it's either a General Radio (with the sloping panel, copper-lined wood case, and bakelite "probe") or a Ballantine (big, black and ugly). I had both of these gadgets as a kid, but alas trashed them before I was old enough to appreciate "nostalgia". Here's a real test of nostalgia: anyone remember acorn-shaped bias batteries? During the early 60's I acquired two pieces of WW II vintage test equipment (a Ferris Instruments RF field-strength meter and a General Radio variable frequency detector) which used them, but by then these batteries were quite obsolete. <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
rbl@nitrex.UUCP (08/10/87)
In article <1911@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes: >In article <504@nitrex.UUCP>, rbl@nitrex.UUCP ( Dr. Robin Lake ) writes: > .... deleted for brevity > > Anyone remember the "junk" sold by Olson Electronics during the >50's and early 60's? ... > I don't know if Olson Electronics is still in business; their >last store in the Buffalo, NY area closed a few years ago. > Olson is still in business in the Cleveland area, selling mostly audio gear. No longer peddling the "junk" stuff. As they were originally based in Akron, this area was peppered with their outlets. From an ad in Friday's paper, it would appear they have taken on the name of a second company, perhaps the result of a buyout or takeover. ><> Larry Lippman @ Recognition Research Corp., Clarence, New York Rob Lake decvax!cwruemcp!nitrex!rbl