|
 As is usually the
case, John Frye uses his monthly "Mac's Service Shop" story to entertain whilst
proffering a valuable lesson in the field of electronics. Mac is famous for his
superb knowledge of electrical principles, and for his ability to troubleshoot
and solve just about any problem put before him. His sidekick technician,
Barney, is a young Ham operator who often needs the admonishment and/or wisdom
provided by Mac. In this 1975 Popular Electronics magazine piece
entitled "Taming
Static Electricity," Barney is saved by Mac from the wrath of office girl
Matilda after she received an electrostatic discharge (ESD) shock intentionally
administered by the young man. Prior to the advent of microelectronic circuits,
everyday ESD was generally...
 While working at RF Micro Devices
(now known as Qorvo) on a project to improve the ESD ruggedness of
our RFICs, I had to do a number of presentations on progress over a span of about
two years. I desperately searched online for this episode of Welcome Back Kotter
titled "Sweathog Clinic for the Cure of Smoking." It was not available
at the time, but did show up for a short time sometime around 2008. Then, it disappeared
and was not available again anywhere until a few months ago when a DVD set for the
Welcome Back, Kotter television series went on sale at Amazon.com.
I quickly snatched a copy and produced this clip...
 "In a statement to the House of Commons,
Minister Al Carns declared that the United Kingdom is committed to defending 'every
inch' of its territory, including its critical
undersea networks and coastal security. The comments came after the Russian
spy ship Yantar entered UK waters earlier this week and was accused of shining lasers
at military pilots. The vessel is being closely monitored by the Royal Navy, having
previously been accused of attempting to map the UK’s submarine cable infrastructure,
The incident follows growing concerns about foreign interference and potential sabotage
to the UK's undersea infrastructure, which forms the backbone for the nation’s energy
supplies and communications..."
 IC designers have been striving to make
the "ideal" opamp ever since the device type was first conceived. An ideal opamp
has a certain set of well-defined properties that permit it be used in circuits
defined by neat mathematical equations without the need for compensating or limiting
terms. An example of compensation might be having an input impedance of something
other than infinite ohms that causes a voltage division effect on the input voltage,
and a limitation would be a gain-bandwidth product that prevents it from being used
in high frequency applications. Opamps appeared in electronics before semiconductors
came onto the scene, and a couple companies attempted to market prepackaged vacuum
tube opamps that plugged into a standard octal...
 I know I keep saying this, but it keeps
being true so I say it again: The
basics of electricity and electronics have not changed in the
last 75 or more years, so these articles from vintage issues of electronics magazines
are as applicable today as they were back then. If you are just getting into the
field of electronics, valuable information can be found here to supplement your
learning process. In fact, I have seen examples in some of these articles where
I re-learned something long-ago forgotten, and some of the stuff is rarely, if ever,
seen in contemporary writings. Regardless, making yourself aware of the work done
by pioneers in the industry is always valuable because it gives you a sense of approaches
taken that have led to success, and sometimes...
 John Mackenzie's 1966 Electronics
magazine article predicted a future where glass would transcend its role as a passive
material to become a primary semiconductor for devices like memories, transducers,
and switches. This forecast has proven remarkably prescient. While crystalline silicon
has dominated mainstream computing, the unique properties of amorphous materials,
now classified under amorphous semiconductors or phase-change materials, have become
foundational to modern technology. The most significant realization of this prediction
is in non-volatile memory, where chalcogenide glasses are the active material in
commercial Phase-Change Memory (PCM) and the memory cells of optical discs (CD-RW,
DVD-RW...
 Reactance charts were a dime a dozen (free,
actually) and appeared as regular features in electronics magazines in the days
before smartphone apps provided ready access to reactance versus frequency calculations.
This one was in the May 1959 issue of Electronics World. Calculators are
nice and indispensible in design work, but sometimes having "the big picture" of
how various values of inductance and capacitance "react" with changes in applied
frequency is often useful - especially if you are a newcomer to electronics. To
paraphrase a popular saying, "A reactance chart is worth a thousand calculators."
 "Researchers at the University of New Hampshire
have harnessed artificial intelligence to accelerate the discovery of
new functional magnetic materials, creating a searchable database of 67,573
magnetic materials, including 25 previously unrecognized compounds that remain magnetic
even at high temperatures. 'By accelerating the discovery of sustainable magnetic
materials, we can reduce dependence on rare earth elements, lower the cost of electric
vehicles and renewable-energy systems, and strengthen the U.S. manufacturing base..."
 My favorite character in the
1970s Prime Time TV show
Barney Miller
was Detective Sargent Arthur Dietrich. He was the serious intellectual with a very
dry sense of humor that came out at just the right moment. One episode has always
stuck out in my memory where a college student claims to have built a working model
of a thermonuclear
bomb as part of his Master's thesis project. All it lacks for detonation, per
him, is plutonium. The on-hand bomb squad expert ridiculed the idea of it being
any kind of real bomb, his decades of experience on the force being his guide
(still has all his fingers as proof of it). All the guys in the office
have just finished...
 Unlike even the vacuum tube type AM radio
in the dashboard of my parents' car in the early 1960s that were self-contained
units, even earlier radios designed for cars and trucks had their bulky electronics
mounted under the sea or in the trunk, with a remote volume and tuning control mounted
in the dashboard. That greatly complicated the installation as well as the design
of the radio. This circa 1940
Belmont Model 678 Auto-Radio is a prime example. Note the unique
cylindrical shape of the radio chassis, and that the remote control is a pushbutton
assembly with rotating knobs for tuning and volume. Operating from a 6 volt DC car
battery (12 volts came later), these radios required a "vibrator" circuit to convert
DC to AC (and back to a higher level DC) in order to transform to a couple hundred
volts for the plate voltage of the tubes...
 When I saw this advertisement for
Monsanto Electronic Instruments in a 1966 issue of Electronics magazine,
I wondered whether it was the same company that makes the controversial Roundup™
weed killer. The Wikipedia entry discusses only the chemical company. Before doing
a Web search on it, I asked AI: "Does Monsanto Electronic Instruments from the 1960s
and 1970s share any company lineage with the Monsanto Chemical Company that makes
Roundup?" It responded: "No, the two companies share a name but no corporate lineage.
Monsanto Electronic Instruments was a subsidiary of the Monsanto Chemical Company
from 1969 until 1979, when it was sold to American Solid State..." To that, I replied:
"Wait, that sounds like it does share lineage." To which it responded: "You're right
to catch that...
 Designing a
log periodic antenna is a piece of cake. Just punch in your computer
program or smartphone app a few parameters for frequency range, power handling,
directivity, impedance, etc., and out pops boom and element lengths, diameters,
and spacings - and probably radiation gain profiles for elevation and azimuth. That
is the way it's done today. However, when Dwight Isbell and Raymond DuHamel of the
University of Illinois came up with the log periodic concept in 1958, they did not
have the convenience of a computer or even a hand-held calculator. Slide rules and
logarithm tables were the order of the day. After trudging through the equations
for building the antenna...
 Who paid for the infrastructure to charge
this beast? Normal users' electric bills have skyrocketed to provide the capability.
It is ironic that there is not a shade of green in this picture. We're also paying
to fund AI and cryptocurrency datacenter energy needs. We've been scammed. Oh well,
at least Big Bro saved us from Covid [sarc]. "The
world's largest
battery-electric ship is now testing the limits of what megawatt-scale charging
and battery storage can do. Unveiled in May by Australian shipbuilder Incat Tasmania,
Hull 096 started receiving electrical charge for the first time last month. The
ship's battery system is 85% installed, with two of its four battery rooms charged
as of publication. The ship's 40 MWhr energy storage system..."
 It was only the first day at engineering
college and already their first familiar techno-caper was underway. Indiana's Parvoo
University was about to get an initiation into the world of
Carl Anderson and Jerry Bishop, who during their high school years
together solved many a mystery and pulled many a prank in their hometown somewhere
in northern Indiana. As with all of John Frye's tales this one mixes serious electronics
topics with a bit of fun and a life lesson. There were no "bad guys" here as in
many other episodes, but the boys did get an unexpected introduction to Parvoo U.'s
president! Despite the story's title, the day ended well...
 In rare final few spare minutes of the workweek,
try your hand at this "Electronics Helix Puzzle," provided by Mr. James Kimsey in
a 1971 issue of Radio-Electronics magazine. It it not as much of a challenge
as a classical crossword puzzle, but is still worth attempting. In some ways, though,
if you get stuck on a word there is more help available with a standard crossword
because there are more than just two (the first and last letter in this case) intersecting
letters available to help. If after completing this Electronics Helix Puzzle you
would like to try your hand at one of those traditional type crossword puzzles,
consider working one (or more) of my weekly...
 Anritsu has been a global provider of innovative
communications test and measurement solutions for more than 120 years. Anritsu manufactures
a full line of innovative components and accessories for
RF and Microwave Test and Measurement
Equipment including attenuators & terminations; coaxial cables, connectors &
adapters; o-scopes; power meters & sensors; signal generators; antenna, signal,
spectrum, & vector network analyzers (VNAs); calibration kits; Bluetooth &
WLAN testers; PIM testers; amplifiers; power dividers; antennas. "We've Got You
Covered."
 It is always interesting to read
industry news stories from decades ago to see when products and techniques that
we take for granted these days were just being introduced. Per this 1966 issue of
Electronics magazine, the U.S. Air Force studied a global network of seismic
arrays, modeled on Montana's Large Aperture Seismic Array (LASA), to detect nuclear
tests. The project aimed for a 10x sensitivity increase, potentially classifying
over 80% of global earth shocks. "High Costs Keep Auto Electronics at a Minimum,"
claimed one headline, its author likely never imagining the overwhelming amount
of electronics in modern vehicles - which still adds significant cost. The Gemini-XI
mission demonstrated a critical first-orbit...
 Pulse modulation comes in many forms, including
pulse position modulation (PPM), pulse width modulation (PWM), pulse frequency modulation
(PFM), pulse amplitude modulation (PAM), and pulse code modulation (PCM). In addition
to providing a nice introduction to the concept of pulse modulation, author Herbert
Kondo covers the basics of each type and then discusses their application in various
communications systems. The first time I recall encountering pulse modulation was
in the mid-1970s with radio control systems for model airplanes. Pulse position
modulation was the scheme used in both AM and FM sets. Modern R/C systems use frequency
hopping spread spectrum (FHSS), direct sequence spread spectrum (DSSS), or a combination
thereof...
Pulse modulation comes in many forms, including
pulse position modulation (PPM), pulse width modulation (PWM), pulse frequency modulation
(PFM), pulse amplitude modulation (PAM), and pulse code modulation (PCM). In addition
to providing a nice introduction to the concept of pulse modulation, author Herbert
Kondo covers the basics of each type and then discusses their application in various
communications systems. The first time I recall encountering pulse modulation was
in the mid-1970s with radio control systems for model airplanes. Pulse position
modulation was the scheme used in both AM and FM sets. Modern R/C systems use frequency
hopping spread spectrum (FHSS), direct sequence spread spectrum (DSSS), or a combination
thereof...
 "An upbeat Elon Musk, with his newly approved
trillion-dollar pay package, talked to a very select group of investors at the Tesla
annual shareholders meeting yesterday in Austin, Texas, and told the audience he
had chips on his brain and planned to build a 'Tera
fab' that could potentially produce a million wafer starts per month to meet
chip demand for Tesla alone. Musk said that all he could think about was chips at
the moment. He also said that with his AI5 chip and the planned AI6 chip, he did
not think existing suppliers could meet demand. As a result, he would consider some
collaboration with Intel..."
 Having worked around resistors and capacitors
for more than four decades comes in handy when presented with 'simple' quizzes like
this one that appeared in a 1963 Popular Electronics dealing with
RC circuits. Still, there is always some trepidation involved
when being subject, even voluntarily, to a test of any sort, regardless of whether
you are fairly confident that it will be a lead pipe cinch, a cake walk, child's
play, so to speak. Even if nobody else will bear witness to your effort, you would
feel like a real moron if you missed even one of those simple questions that anyone
with your level of experience should get right without even having to think about
it. Such is the irrational fear I have when taking these quizzes...
• FCC Intent to
Delete Minor Part 97 Provisions
• Intel
Retreat Shifts EU Semiconductor Reality
• GSA Reports
Evolving Global Spectrum Strategies
• UK Telcos Secure
mmWave Spectrum
to Boost 5G
• 41% of
Schools Report AI Cyber Incidents
 While this article is directed at amateur
radio operators who want to explore working in the microwave bands, it is good fodder
for anyone who wants a fundamental introduction to
waveguides, resonant cavities, distributed elements, and atmospheric
propagation. If that describes you, and particularly if you have formulaphobia,
then start reading. Even though the article appeared in a 1952 issue of Radio &
Television News, the list of frequency band allocations are not much different
than today so the information is useful. Unknown to many is that in the early part
of the last century Amateurs pioneered the use of microwave bands when the Federal
Communications Commission (FCC) allocated the spectrum to them since many "experts"
considered it unusable...
 Empower RF Systems is the technological
leader in RF & microwave power amplifier solutions for EW, Radar, Satcom, Threat
Simulation, Communications, and Product Testing. Our air and liquid cooled amplifiers
incorporate the latest semiconductor and power combining technologies and with a
patented architecture we build the most sophisticated and flexible COTS system amplifiers
in the world. Solutions range from tens of watts to hundreds of kilowatts and includes
basic PA modules to scalable rack systems.
 Integrated circuits were just entering the
mainstream of electronics in 1966 when this two-page
Motorola spread appeared to promote some new monolithic IC amplifier products.
Monolithic means everything is contained on a single substrate, as opposed to a
hybrid circuit with an IC die and one or more discrete components contained inside
a can. You'd have to be an old guy (like me) to realize that High-Speed Core Memory
Sense Amplifier refers to one of four wires (x-axis, y-axis, sense, inhibit) that
were threaded through magnetic core memories in use before monolithic memory was
available. As reported in this same issue...
 This story from a 1964 issue of Electronics
magazine is close to home - literally. Well, it was close to home at the time, anyway.
It reports on the work done by the
Electromagnetic Compatibility Analysis Center "...jutting out
on a pier across the broad Severn River from the United States Naval Academy at
Annapolis." I grew up in the 1960s and 70s just a few miles from there and distinctly
recall seeing all the antennas in the area, including the now decommissioned and
removed acres-big ELF submarine communications antenna farm. The Annapolis location,
with its proximity to Washington, D.C., was the home to many government and military
installations and defense contractors. It was an electromagnetic signal-rich environment...
|
The RF Cafe Homepage
Archive is a comprehensive collection of every item appearing daily on this
website since 2012 - and many from earlier years.
 For many years, I have been scanning and
posting schematics & parts lists like this one that appeared in radio and electronics
magazines in the middle of the last century. Most use vacuum tubes. This
General Electric Model 280 Farm Radio "Radio Data Sheet" was in the May 1947
issue of Radio-Craft. The Radio Museum website has more information on the GE Model
280 Farm Radio. Farm radios were designed to work on storage batteries since until
the Rural Electrification Act of 1936 was put into effect, most rural properties
had no commercial AC electric power service. 11 years later, work was in progress
to light up the entire country, but many locations had to wait while resources went
to service war production needs. No actual example of the Farm Radio could be found
online. There are still many people who restore and service these vintage radios...
 If you believe this 1953 advertisement in
Radio & Television News magazine, engineering at Bell Telephone Laboratories
invented the
wire-wrapping process. A little additional research shows that indeed it
was a Bell Telephone engineering team led by Arthur Keller who developed the
method and a wire-wrap tool to do the job. Field technician needed a fast,
durable, and reliable electrical connection when making hundreds or thousands of
splices at relay stations and while up on telephone poles. The key to making a
good wire-wrap connection is sharp corners on the wrapping post so that the
corner pushes through any oxidation or contaminant on the bare wire. NASA and
the DoD have exacting workmanship standards to guarantee...
 As with my hundreds of previous
engineering and science-themed crossword puzzles, this one for
December 8, 2019, contains only clues and terms associated with engineering, science,
physical, astronomy, mathematics, chemistry, etc., which I have built up over nearly
two decades. Many new words and company names have been added that had not even
been created when I started in the year 2002. You will never find a word taxing
your knowledge of a numbnut soap opera star or the name of some obscure village
in the Andes mountains. You might, however, encounter the name of a movie star like
Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which,
if you don't already know, might surprise you...
 The
National Radio Institute (NRI) was one of the first country-wide organizations
to offer formal electronics training both as classroom and as self-study courses.
Magazines were filled with offers to train men in what was an exciting new career
field. The drums of war were beating in the background in Europe and the South Pacific
by December 1940 when this article appeared in National Radio News, and
the U.S. military was gearing up for what was sure to be an eventuality. Three months
earlier, the Tripartite Pact united Japan, Italy and Germany to formalize the Axis
Powers, and Hitler's forces had invaded Western Europe. The push was on to train
a large number of engineers and technicians to handle communications and control
systems for Army and Navy forces. It is always interesting to read pieces penned
at the time events were unfolding, rather than after having been filtered through
the worldview of subsequent authors...
 In the 1960s, most people believed that poetry
ought to rhyme. It was not uncommon to see poems appear in magazines of all sorts
including even technical publications like Popular Electronics. "More
'Tower' to You" is a good example. Nobody ever claimed that these reader-submitted
on-subject poems were of Nobel Prize quality, but many were extremely clever and
were almost sure to elicit the chuckle their authors intended; that is to say, they
were humorous. What made them humorous is what is true of nearly all good humor
- it contains an element of truth...
 If you are familiar with aircraft electronic
navigation systems, reading in this 1951 Radio-Electronics article's opening
paragraph about how "Omnirange
aircraft navigation will make air travel safe, dependable, and predictable regardless
of visibility, and volume of air traffic," really makes you realize how far we have
come in the last seven decades. The network VOR (VHF Omnidirectional Range) station
revolutionized aviation by enabling precision navigation using relatively simple,
reliable, and inexpensive equipment in the cockpit which enables pilots to fly from
waypoint to waypoint across the country. Eventually, five variations of VOR evolved
with ranges going from 25 nautical miles (~29 statute miles) up to 130 nm.
The addition of TACAN (TActiCal Air Navigation) provided slant distance information
to or from the VORTAC station. Since the introduction of full precision GPS, when
the U.S. government unclassified the "P-code"...
 Here is a bit of
history of the field effect transistor's (FET) history presented in a 1965 issue
of Electronics World magazine. Author Gene Jackson mentions how the FET was being
researched in laboratories toward the end of World War II, predating the junction
type transistor developed by Ball Labs, with the first working model announced in
late 1947. A primary difference between the bipolar junction transistor (BJT) and
the junction FET is that the BJT is current-controlled and the FET is voltage-controlled
(like a vacuum tube). The abbreviation JFET is not mentioned in reference to the
junction FET, although MOSFET is used for the metal-oxide-semiconductor FET. Magazine
editor William Stocklin adds a comment about the difference between electron current
flow (negative to positive) and conventional current flow (positive to negative),
which was a relatively new distinction at the time. See the follow-on article...
 The first electronic circuit I remember building
as a budding teenage tinkerer was a
"whistler" detector, aka a "sferic." Instructions and a schematic came from
a project book I bought at Radio Shack. A whistler is a time-varying electromagnetic
signal that decays in both frequency and volume over a short time - like sounds
made by the eponymous fireworks genre. Having always had an interest in weather
phenomena as part of my flying hobbies, it seemed like an apt learning endeavor.
To my recollection, the whistler detector was a simple diode circuit with a couple
Rs, Ls, and Cs strewn around in a particular configuration, and a long wire antenna.
I can't honestly say whether or not any whistlers were ever heard with it. My interest
was a layman's curiosity, but elsewhere in the world, professional scientists were
expending a lot of effort in their attempts to analyze and quantify a whitler's
particulars...
 Anyone who watched the
WKRP in Cincinnati
sitcom back in the 1970s has to remember what was one of the funniest episodes ever.
Here is the 4 minutes that made Prime Time history. In this Thanksgiving episode,
station owner Arthur Carlson decided he would surprise the community with good deed
- that doubled as a promotional stunt for his radio station - by dropping turkeys
from a helicopter for lucky shoppers at the local shopping mall. Watch the disaster
unfold as Les Nessman reports live, and then see Carlson's final comment that is
still used or alluded to in many comic routines. Posting this video is an RF Cafe
tradition. Have a Happy Thanksgiving!
 This item from Tarek Mealy showed up on
my LinkedIn feed. He created a nifty software app called "SymMos" that allows
you to use a drag-and-drop interface to create a schematic using MOSFETs, resistors,
inductors, capacitors, bias voltages, and signal sources. Then, click on the appropriate
button to get the transfer function equation for input impedance, gain, transconductance,
or noise figure. SymMos is a work in progress and is available as a free download.
After unzipping the file, you need to change the SymMos.txt file extension to .exe.
Launch the executable and then you'll need to wait many seconds while the program
loads (a black screen is displayed while waiting). BTW, Norton flagged the file
as dangerous since it is new and hasn't seen it before, but I allowed it to run
anyway with no problems. I recreated the example shown in the YouTube video and
it works as advertised...
 Today's
ceramic capacitors are vastly different from most of those from
the middle of the last century. While the ceramic capacitor in your modern electronic
circuit is likely in the form of a thin circular or rectangular package, or of a
tiny surface mount outline, those described in this Radio-Electronics magazine
article were rather large tubular devices that had the appearance of a wirewound
power resistor. The advantages of ceramic capacitors over other types available
in the 1950 (paper and mica) are basically the same as today - high voltage handling
and tight tolerances of down to ±1%. Table I lays out a comparison. Wikipedia
has an extensive comparison of modern capacitor types, illustrating how far technology
has advanced since then...
 There is a physical limit to how small of
a distance may separate two distinct objects (line, dots, etc.), generally agreed
to be about half a wavelength of the color being observed, and be seen with perfect
human eye. Applying that rule of thumb to blue light with a wavelength of approximately
4000 Å (400 nm) yields a distance of 200 nm. Accordingly, there is
no amount of magnification possible which will allow a healthy human eye to resolve
objects closer together than that. Even with perfect optics, magnifications of greater
than about 1500x are not able to render greater detail. To resolve smaller distance
requires shorter wavelengths, but we cannot see them directly and need a device
to transform the detected image into a visible image. That is what an
electron microscope does to enable molecule sized particle to be "seen." The
SARS-CoV-2 particle has been measured by electron microscopy and found to range
between 50 to 140 nm, so it cannot be viewed directly with an optical microscope.
Cigarette smoke is about 400 nm in diameter...
 You have probably seen some pretty atrocious
coaxial cable connector installations. You might have even been responsible
for a few of them ;-( It could be tempting, at least for frequencies
in the lower megahertz range, to allow yourself to be a little sloppy with coaxial
cable preparation and connector attachment, but doing so can result in marginal
functionality if power levels are high or if power levels are extremely low. When
voltage levels are high, excessive air gaps between the inner and outer conductors
can result in arcs, and poor connections can generate intermodulation products high
enough to cause interference (possibly subjecting you to a violation citation from
the FCC). At very low power levels, distortions and lack of symmetry in the interface
between the cable and the connector...
 An article
titled "One Receiver - All Bands" that appeared in the January 1963 issue
of Popular Electronics was a single tube receiver design, but the trick
to using a single tube was that the it was actually three tubes in one - a 6AF11
compactron.
It contained two separate triodes and a pentode within the same glass capsule. A
modern equivalent would be to use an integrated circuit (IC) package that contains
three or more opamps in the same package. In fact, variations on compactrons that
included internal biasing components were referred to as integrated circuits. This
article from the October 1960 edition of Electronics World reported on
the engineering behind compactron vacuum tubes...
 Gray market electronic components are not
just a recent problem. Long before IC foundries were set up in China, Indonesia,
Vietnam, etc., to produce counterfeit semiconductor components, there were unscrupulous
manufacturers turning out bogus components of all sorts. Marking unauthorized microprocessor
and amplifier packages with an industry-leading brand name and part number is a
real problem, but such practices extend back to the vacuum tube era. This story
from a 1957 edition of Popular Electronics magazine tells the story of
how companies like General Electric and Sylvania dealt with the situation...
 When this self-promotion of progress made
on the
transistor invention by Bell Telephone Laboratories appeared in the June 1952
issue of Radio-Electronics magazine, a mere three and a half years had
passed since the announcement of the achievement by Drs. Bardeen, Brattain, and
Shockley. Interestingly, it refers to germanium as a metal rather than as a semiconductor.
In that interim, many problems had been solved in the effort to make robust, reproducible
devices that were affordable replacements for vacuum tubes. One of the primary differences
between the most recent transistors and the early models was the use of doped junctions
rather than point contacts. This made them more resistant to effects of vibration,
temperature changes, and contamination, and also produced higher yields in manufacturing.
Gaining the confidence of designers was imperative if the newfangled technology
was to gain (pun intended) ground as the preferred component for amplifier, oscillator,
mixer, and other type of circuits traditionally...
 The August 1972 issue of Popular Electronics
included a short quiz by William Shippee titled "Test
Your Knowledge of Semiconductors." I guessed wrong on question #2, but guessed
right by process of elimination on question #8 (although afterward I discovered
that in 2012 I had posted an article about the #8 device in Electronics World
magazine). Go ahead and take your best shot. You might be surprised at how much
you've forgotten if you don't work with transistors on a regular basis. I'll bet
Q2 has most people guessing, too...
 "Necessity is the mother of invention," is
an oft-heard maxim that is validated continually. Such was the case, as pointed
out here in this National Union Radio Corporation ad which appeared in a 1944 issue
of Radio-Craft magazine. The development of many new metal alloys was required
in order to obtain the kind of performance and reliability needed in ever-evolving
electronics products. Already available metals for filaments, coils, grid wires,
getters, electron guns and many other constituents of
vacuum tubes that are subject to high temperatures (many hundreds
of degrees) and mechanical conditions (unequal coefficients of expansion, for example,
which can cause stress fractures), were not sufficient for the task. Metallurgists
had their work cut out for them... |
