The December 1969 issue of
Radio-Electronics magazine's "New & Timely" column reported that at the
National Electronic Association conference,
technicians reported burns and eye damage caused by X-radiation from color TV
sets under repair. Night vision scopes for commercial use were introduced by
Raytheon, suitable for law enforcement, industrial security, and nature study. A
joint U.S.-Indian plan planned to beam TV directly to millions of Indian
villagers via a stationary applications satellite in 1972. The French Atomic
Energy Commission used a superpowerful laser to create minute thermonuclear
explosions, fusing deuterium...
Anatech Electronics offers the
industry's largest portfolio of high-performance standard and customized
RF and microwave filters and filter-related products for military,
commercial, aerospace and defense, and industrial applications up to
40 GHz. Three new filter models have been added to the product line in April,
including a 5500 MHz WiFi cavity bandpass filter, a 3437-3537 MHz ceramic
duplexer filter, and a 1425 MHz cavity bandpass filter. Custom RF power filter
and directional couplers designs can be designed and produced with required
connector types when a standard cannot be found, or the requirements are such
that a custom approach is necessary...
This article published in a 1955 issue of
Popular Electronics magazine is a really good primer on the history and
working principles of the
electron microscope. It also explains why such a device is needed;
i.e., why an optical microscope cannot do the job when really high levels of magnification
are required. As object dimensions are spaced at distances near to or less than
the optical wavelength being observed, it becomes impossible to resolve into separate
features. Accordingly, when observing at the upper end of the visible light spectrum
at around 400 nm, under ideal conditions you would not be able to clearly discern
two feature less than about 800 nm apart. Current (2019) CMOS gate thicknesses
run about 5 μm, so visible light cannot be used to image those structures.
Another resolution limiting factor is aperture size, which, depending on the wavelength
causes diffraction patterns of two objects to overlap...
If you are a seasoned vintage electronics
equipment aficionado, restorer, hobbyist, etc., then you most likely already have
your own list of supply sources for vacuum tubes. Contrary to what others might
think, there is still a healthy stock of tubes available from private websites like
Pacific T.V. (hat tip to Bob Davis), as well
as collective sites like eBay, Facebook Marketplace, Craigslist, and vintage electronic
equipment forums. Prices for common tubes are surprisingly low if you shop around.
If you need an output power amplifier for a commercial radio station, be prepared
to shell out major wampum, though. Many NOS (new old stock) varieties in original
boxes can be had, as well as used tubes. Most have been tested for specification
compliance.
Westinghouse is yet another bulwark company
of America's foundational industrial age, beginning in the late 19th Century. George
Westinghouse founded eponymously-named company,
Westinghouse Electric & Manufacturing Company, in 1886, during the time
he was working with Nikola Tesla (I wonder whether any of the current-day anti-Tesla
nimrods are stupid enough to vandalize NT statues and monuments?) to institute a
commercial electrification infrastructure. Mr. Westinghouse began his life
of fame and fortune with a locomotive air brake design. During World War II,
Westinghouse's many locations designed and manufactured many types of products to
facilitate troops in all Theaters of Operation. This 1943 issue of Popular Mechanics
magazine carried a full-page...
This set of three circuit analysis challenges
appeared in the January 1963 issue of Radio-Electronics magazine. Readers,
staff, and even come companies submitted the "What's
Your EQ?" (EQ = Electronics Quotient) content. As an example of the latter,
Cleveland Institute of Electronics provided "Draw the Waveform." Don't let the diode
vacuum tube deter you from the puzzle. Just mentally replace the tube with a solid
state diode symbol with the anode at the top where the tube's plate (anode) is shown.
The negative element of a tube is called the cathode, same as the solid state diode.
"Capacitor Charge" is easy enough. "Another 2-Box Light"...
"Despite increasingly intense competition
for skills across all sectors of industry and a growing appetite amongst engineers
for a new challenge, engineering salaries appear to have stagnated over the past
12 months. This is just one of the key findings of The Engineer's tenth
annual salary survey, which is published in full on The Engineer's website
in a new interactive digital format. Attracting responses from 621 engineers working
across 12 different sectors, this year's survey was carried out between December
2024 and January 2025. As ever, the results provide a fascinating insight into
UK engineering salaries and how engineers are feeling about their careers..."
In this 1963 issue of Radio-Electronics
magazine, editor Hugo Gernsback reflects on the early days of television, noting
that the first regular daily TV broadcast began on August 13, 1928, over radio stations
WRNY and W2XAL, which were associated with his former publication, Radio News.
Initially, these
broadcasts were silent, featuring only moving images the size of a postage stamp,
and it wasn't until 1931 that TV broadcasts included sound. Gernsback critiques
the slow progress in improving the audio quality of television receivers, pointing
out that despite advancements in high-fidelity and stereo audio technology, most
TV sets still lacked these features due to regulatory restrictions by the FCC. He
expresses hope that recent petitions to the FCC...
Exodus Advanced Communications, is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Exodus' model
AMP20081 high power solid state power amplifier (SSHPA) is ideal for broadband
EMI-Lab, communications, and EW applications. Class A/AB linear design accommodates
all modulations & industry standards. It covers 80-1000 MHz, producing
600 W nominal, with a 500 W P1dB and 56 dB minimum gain. Excellent
flatness, optional monitoring parameters for forward/reflected power, VSWR, voltage,
current & temperature sensing for superb reliability and ruggedness...
In that these
comics from Radio-Craft magazine have an electronics
theme, you can claim looking at them is work-related. The themes of the comics reflect
common scenarios of the 1944-1945 era in which they were published, but with not
much modification can be applied to today's environment. People will always expect
more features from products, will be critical of everything presented to them, and
will want to haggle for the best deal from the used camel salesman. You might consider
using one of them for your next conference or project status presentation. There
is a list of many more similar comics at the bottom...
In a groundbreaking announcement that will
forever transform global communications, QentComm®©™ (Quantum Entanglement Communications)
has unveiled the world's first
commercially viable quantum entanglement communication system. Dubbed QeG®©™
(Quantum entanglement Generation, pronounced kwee-gee), supplementing the traditional
4G, 5G, and 6G nomenclature, this revolutionary technology eliminates the limitations
of traditional radio-based systems, delivering instantaneous, unlimited connectivity
across any distance without reliance on satellites, cell towers, or fiber optics.
Under the leadership of Kirt Blattenberger, QentComm (pronounced kwent-kahm) has
created a system that defies conventional physics by utilizing quantum entanglement
for real-time, secure communication between devices anywhere in the universe - including
here on Earth...
In this "Carl & Jerry" technodrama from
a 1957 issue of Popular Electronics magazine, the two boys start out enjoy a casual
day of kite flying, using a homebrew radio-controlled camera attached to the kite
to capture an aerial view of Round Island in a lake. After successfully taking a
picture, they develop the film and discover two men and an odd setup on the island.
Curious, they return the next day, find a hidden tunnel, and stumble upon an illegal
liquor still. As you might expect, the teens run into a heap of trouble when the
moonshiners nab them. Using their combined ingenuity and knowledge of communications
methods common to Ham radio operators of the era, contact was made and help was
on the way. Read about Carl and Jerry's exploit and exactly what it was that saved
the day - and their hides!
"In late January 2025, 17 students and staff
members from Las Animas High School (LAHS) in Colorado visited the
Deep Space Exploration Society Radio Telescope (DSES) located at the Plishner
Radio Astronomy and Space Sciences Center near Haswell, Colorado. They also got
an introduction to amateur radio. 'This first field trip visit of high school students
reflected the dreams of Michael Lowe, former DSES board president, who sought to
create a center for radio astronomy and space science education in southeast Colorado,'
said DSES President Myron Babcock, KL7YY..."
Making format changes to magazines after
many years of an established standard always ruffles the figurative feathers of
a significant portion of regular readers. Two magazines I read monthly, Model
Aviation and QST, recently underwent a format change - both of which
I considered very nice. However, reader comments in the aftermath showed a few who
were not impressed. Popular Electronics magazine in 1966 made announcements
regarding plans to adopt some of the
newer base units for physical measurements, including this one for beginning
to use "Hertz" (Hz), along various numerical prefix forms, instead of "cycles per
second" (cps). The editors give sound reason...
The
Beverage Antenna, very familiar to amateur radio operators, is
a simple but efficient, highly directional, non-resonant antenna that consists of
a single straight wire of one or more wavelengths that is suspended above the ground.
It is orientated parallel to the direction of intended reception. One end is terminated
to ground through a resistor, and the other is connected to the receiver. The following
quote comes from the patent (US1,81,089) text: "In accordance with theoretical considerations,
if an antenna were to be freely suspended and if the surface of the earth constituted
a perfectly conducting parallel plane, current waves would travel through...
This letter was sent to Hugo Gernsback,
publisher of Radio-Electronics magazine, in response to the "30-Day
Record Response" article penned by noted scientist and inventor Mohammed Ulysses
Fips. In it, Stephen A. Kallis, Jr. heaped laud upon the "Most Revered and Esteemed
Fips" for his long-term recording device (remember, 1961 was many decades before
microminiature terabyte memory and microprocessors) were available, and chastises
Mr. Gernsback for evidently calling into question the authenticity of the recorder.
Kallis, a self-proclaimed stereo enthusiast, bolsters Fips' case by citing "A Proposed
Listening Area," by the Institute of Synergistic Statics Proceedings...
Raise your hand if you're old enough to
remember doing printed circuit board layout using
Rubylith tape. My hand is up. Back in the early 1980s, I did prototype
PCB designs in an engineering development lab at Westinghouse Electric's Oceanic
Division. Most of it was for analog and RF substrates that would be photographically
reduced in size for use with bare integrated circuit die and surface mount passive
components (Rs, Ls, and Cs), upon which I would later epoxy-mount those components
and wire-bond everything using 1-mil gold wire. However, there were projects where
full-size leaded components were used on a through-hole PCB that used not only the
Rubylith tapes but also sheets with special electronics shapes for solder pads around
the holes for components leads, ground and power planes, board-edge connectors...
"Quantum systems don't just transition between
phases - they do so in ways that defy classical intuition. A new experiment has
directly observed these
dissipative phase transitions (DPTs), revealing how quantum states shift under
carefully controlled conditions. This breakthrough could unlock powerful new techniques
for stabilizing quantum computers and sensors, making them more resilient and precise
than ever before. A new frontier phase transitions, like water freezing into ice,
are a familiar part of everyday life. In quantum systems, however, these transitions
can be far more extreme, governed by principles like Heisenberg's uncertainty..."
In
this November 1940 issue of the Boy Scouts Boys' Life magazine, amateur
radio operators, or "hams," are described as having the ability to communicate across
vast distances, connecting far-flung locations such as Goulds, Florida, Cali, Colombia,
Cairo, Kenilworth, England, Bombay, and Brisbane. These operators, licensed by the
Federal Communications Commission, engage in various activities such as talking
to distant stations, participating in contests, and providing emergency communication
during natural disasters. With call letters assigned by international treaty, these
stations use a combination of code and phone to make contact, exchanging reports
and QSL cards. The
Radio merit badge was first offered in 1918 and has been...
ConductRF is continually innovating and
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and phased matched VNA applications as well as standard & precision RF connectors.
Over 1,000 solutions for low PIM in-building to choose from in the iBwave component
library. They also provide custom coax solutions for applications where some standard
just won't do. A partnership with Newark assures fast, reliable access. Please visit
ConductRF today to see
how they can help your project!
The date approacheth when, according to
Western customs, every body needs to stand a vigil against the attempt of another
body to make him or her a fool. That date is of course April 1st, aka, April
Fools' Day. Many of the technical magazine we grew up with - and some still today
- engage in the ruse. Innovator and publisher Hugo Gernsback, who's long list of
accomplishments includes this Radio-Electronics magazine, often contributed
his own wit to the April editions. The usual scheme is to make the article just
authentic enough to be possibly real, while including features outrageous enough
to clue the read that he is being "had." Experienced subscribers knew that the Mohammed
Ulysses Fips byline was sure to deliver an April Fools delight. Here, Mr. Fips
expounds on the newfangled "Electronics
Razor..."
"Quantum computing has long struggled with
creating
entangled photons efficiently, but a team of researchers has discovered a game-changing
method using metasurfaces - flat, engineered structures that control light. By leveraging
these metasurfaces, they can generate and manipulate entangled photons more easily
and compactly than ever before. This breakthrough could open the door to smaller,
more powerful quantum computers and even pave the way for quantum networks that
deliver entangled photons to multiple users..."
Here is a chart you don't see every day
- "Temperature Rise in Rigid Waveguide." The company, Engineering
Antenna Systems, of Manchester, New Hampshire, that published the chart in a 1965
edition of Engineering magazine, does not exist anymore. They were probably
bought by someone else, but I could not even find an honorable mention of them in
a Google search. Given the very low attenuation of properly sized and installed
waveguide, it is hard to imagine a temperature rise of 500°F; however, when megawatts
are pumped into it even a couple tenths of a decibel of attenuation per 100 feet
results in a lot of power loss. Noted is how attenuation - and therefore temperature
rise - is greater for frequencies at the lower end of the waveguide's operational
range. Temperature rise numbers are for natural convection in free air...
Here is an inspiring interview of
Werbel Microwave's Ernest Werbel - a case of pulling oneself up by one's own
bootstraps --- everything RF recently interviewed Ernest Werbel, the Chief Design
Engineer of Werbel Microwave. He is from Livingston, NJ, and got his associates
in EE Technology, at County College of Morris. Ernest completed his Bachelors in
Electronics and Computer Engineering Technology from NJ Institute of Technology.
He founded Werbel Microwave in 2014. Q. Can you tell us about Werbel Microwave?
When did you start the company and how has it evolved over the years? Ernest Werbel:
Firstly, thank you for the opportunity to participate in the everything RF community.
I appreciate everything that Raghav and his team have done for us since the beginning,
getting our products listed on everything RF and featuring our products in the email
blasts... As a child and teen in the 90s, I was always interested in electronics.
When I was very young, a radio was a magical box with a voice. Later, when my grandparents
passed in '97, my parents and I were cleaning out their home in Brooklyn. Among
other things were many old and broken consumer electronic items...
Today we have
missing persons notices printed on milk cartons and computer-aged
pictures of missing kids on bulletin boards at Walmart, and of course the Internet
with all its various forms of publicity. In 1935, evidently, an electronics magazine
was a proper venue for placing a missing person ad. At the time there was no convenient
and accessible way for family members to reach out to a nationwide audience other
than to place ads in magazines and/or newspapers in remote locations. I thought
it odd to see such a placement in this edition of Short Wave Craft magazine,
but considering the aforementioned, doing so is entirely reasonable for a worried
family. I wonder how much it cost to place the notice? It's heartbreaking, really...
• 2025 Tech Jobs Expected
to Take Off
• Semiconductor
Industry Faces a Seismic Shift
• 76% of
News Consumers Still Use AM/FM
• FCC
Spectrum Rules to Support Advanced Flight Technologies
• Radio
Attracts High Purchasing Power Consumers
I'm always aware of the old saying that
it is better to remain silent and thought a fool, than to open your mouth and remove
all doubt, but I'll take the risk here. The ARRL's QST magazine has for
decades in the April issue published at least one unannounced "April Fool" item.
I think I found at least two for 2025. While enthusiastically reading "Turn Your
Vertical Antenna into a Rotatable Beam," (p60), it didn't occur to me that this
was the April issue, and I was in awe of Jay Kolinsky's (NE2Q) intuition and creativity
in devising a scheme to get directivity from his standard vertical whip antenna.
By sliding a carbon fiber tube with a narrow slit along the length over top of the
antenna, a 14 dB increase was realized in the direction of the slit. NE2Q has
named his invention the Loof Lirpa Slot (LLS). What's in a name -
Juliet?.
Is a patent in the works?
The other suspect is the CW Corp. of America's
"Snappy
Training Key," reported on page 95 by Ellwood Brem (K3YV). You need to log in
to read the articles, or borrow a hard copy from a Ham friend.
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Here is another of the "Radio
Term Illustrated" type of comic, which appeared in the December 1939 issue of
Radio News magazine. The DXing Hams can get a bit animated when trying
to squeeze the last picowatt out of a long distance contact. I'm not sure why the
guy is depicted as a country hick when for certain there were plenty of polished
city slickers who resorted to the same antics. A big list of other electronics-themed
comics is at the bottom of the page, many of which contain other of the "Radio Term
Illustrated" style.
Radio Amateur News began life in
July 1919, then changed its name a year later in July 1920 to Radio News.
In August 1948 the title was again changed to Radio & Television News,
then shortened to Radio & TV News in May 1959. Publication continued
through April 1959. The next month's issue (May 1959) was entitled Electronics
World, with Radio & TV News as a subtitle, and ran through December
1971, when it merged with
Popular Electronics. Popular Electronics began publication as
a new magazine in October 1954 and printed its final issue in October 1982. The
next month it became Computer & Electronics, which continued until
April 1985. From May 1985 through January 1989 it was called Hands-on Electronics.
Believe it or not, in January 1990...
It has been a while since posting on of these
Radio Data Sheet 333 that often appeared in vintage electronics magazines like
Radio-Craft. This one is for
General Electric Radio Models 100, 101, 103 and 105. The RadioMuseum.org website
has a very nicely restored General Electric Model 103 radio. Per their description:
"The General Electric 103 is an AC/DC operated 5 tube BC band receiver. The BC band
frequency tuning range is 540-1600 kHz. Has built-in loop antenna with provisions
for connecting an external antenna. The following models use the same schematic
and chassis but have different cabinets..." A few Model 100 versions show up on
eBay in case you might be interested in acquiring one...
Audio distortion is most often expressed as total
harmonic distortion (THD) as opposed to
intermodulation distortion (IMD). As the name suggests, THD is a measure of harmonic
power content relative to the fundamental frequency (a single tone) from which harmonics
are created. IMD on the other hand, is generated from the nonlinear mixing of two or
more tones, with the products being non-harmonically related to the original tones. The
author's discussion of audio frequency IMD applies equally to radio frequency IMD. Intentionally
generated harmonic components can enhance sound quality due to being consonant, whereas
IM products create dissonant tones not directly related to the originals...
This is the eighth and final installment
on a "Microwaves" series of articles in Radio-Electronics magazine by author
C.W. Palmer. Each part is a stand-alone tutorial that does not rely on previous
parts to be useful. Unlike most of the preceding articles that dealt in one way
or another with waveguide, this final one concerns "receiving
and transmitting antennas for microwave communication." It touches lightly on
various types of antennas, field patterns, impedance matching, and applications.
If you've been around for a while, you've likely seen it all before, but there are
some nice photos of antennas designed and deployed by Bell Telephone Laboratories
for their nationwide microwave telephone relay network. Bell Labs has done a lot
of ground-breaking research in all aspects of communications technology...
Feedback has been widely misunderstood by
many electronics enthusiasts, even those who have a fairly extensive background
in circuit design (that which does not involve
feedback). In fact, there have been instances of articles being printed in magazines
like Popular Electronics, Radio-Electronics, etc., where the
authors got relatively simple feedback equations wrong due to improper summing
of nodes, necessitating a correction in a later issue based on reader feedback
(a convenient and appropriate word for this comment). This article discusses
feedback in audio circuits to avoid distortion, but the concepts apply to any
frequency of operation. It is possible in many cases to implement
seat-of-the-pants feedback schemes successfully, but if you need a specific
response and guaranteed stability...
Before there were side-view neon numerical indicator
vacuum tubes there were top-view neon
numerical
indicator vacuum tubes. Nixie tubes and pixie tubes were featured in "Readouts and
Counter Tubes" in the October 1959 issue of Electronics World magazine. At the
time, most were top-view designs whose size was restricted by the diameter of the tube
(typically about 0.8"). Switching to a side-view format did not enable the overall width
to increase much, but the aspect ratio permitted taller displays with characters that
appear as normally seen (rather than being squashed in height). This advertisement in
a 1965 issue of Electronics magazine for numerical indicator tubes from
Raytheon were likely some of the first side-view models available from any
manufacturer...
This letter submitted to Electronics
magazine by reader Fred Standish really should have been saved for the next
April issue. He writes concerning an attempt to mathematically describe the
three-port circular-to-rectangular waveguide transition for the pictured configuration.
If I remember correctly, the first time I saw that optical illusion was sometime
in the early 1970s. The drawing showed Alfred E. Neuman (the red-haired, freckled-faced
"Me Worry? guy from Mad magazine) attempting to don a pair of pants (a
triplet of pants in that case?) sewn to resemble the three-legged configuration
- known unofficially as the "Impossible Trident." I was in my early teens at the
time and though it was awfully clever. After doing a little research, I found that
the first instance of the Impossible Trident in Mad magazine was on the
cover of the March 1965 issue ...
Here is a quick
Hi-Fi Quiz for all you audiophiles out there. Although it appeared in a 1955
issue of Radio & Television News magazine, save for question #10 all
of Q's and A's still apply to today's equipment. Even that one can be easily guessed.
Q4 might seem a bit foreign, but think of the "groove" type as applying to 78, 45,
or 33-1/3 rpm platters and you'll do OK. Question #7 could be a baffler (pun intended
- you'll see how) were it not for one obviously invalid option that it takes an
RF guy (or gal) to recognize its inanity. Good luck. BTW, I missed Q1, but should
have known better.
This week's crossword puzzle will keep you
busy for a while. Since 2000, I have been creating
custom engineering- and science-themed crossword puzzles for the brain-exercising
benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury
is out on whether or not this type of mental challenge helps keep your gray matter
from atrophying in old age, but it certainly helps maintain your vocabulary and
cognitive skills at all ages. A database of thousands of words has been built up
over the years and contains only clues and terms associated with engineering, science,
physical, astronomy, mathematics, chemistry, etc. You will never find a word taxing
your knowledge of a numbnut soap opera star or the name of some obscure...
Founded in 1921 in Salem, Massachusetts,
Hytron Corporation started out making vacuum tubes, then after being bought by CBS
in 1951 they moved into the realm of semiconductor production. This story from a
1944 issue of Radio News magazine extolled the virtues of
Hytron's Master Test Station for its ability to quickly and accurately measure
a wide variety of tubes. Auto-ranging voltage regulators, parallax-free meters with
auto-ranging scales, safety fusing, and easy servicing were among it notable features.
To me, a parallax-free meter is one with a mirror behind the needle used to assure
the operator is looking straight-on at the scale, but in this case it meant the
array of meters was arranged in a semi-circle so that the operator was naturally
looking perpendicular to the meter faces from a fixed vantage point. The level of
automation no doubt reduced measurement errors...
RF Cafe visitor Jeff B. of Beverly, MA, sent
me these photos of his
General Electric Model M-49, 4-tube radio-phonograph, dual-wave superheterodyne set
that he is going to restore to working order. It appears to be in extremely nice condition
for a 1930s era unit. He found the Radio Service Data Sheet from a January 1935 issue
Radio-Craft magazine that I posted back in October 2016. These are now
the only images of the M-49 anywhere I can find on the Internet...
This
RF Cafe Engineering & Technical Headlines Crossword Puzzle contains at least
10 words from headlines posted on the homepage during the week of September 16 through
September 20, 2019 (marked with an asterisk*). These custom-made engineering and
science-themed crossword puzzles are done weekly for the brain-exercising benefit
and pleasure of RF Cafe visitors who are fellow cruciverbalists. Every word and
clue - without exception - in these RF Cafe puzzles has been personally entered
into a very large database that encompasses engineering, science, physical, astronomy,
mathematics, chemistry, etc. Let me know if you would like a custom crossword puzzle
built for your company, school, club, etc. (no charge).
With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils
available for RF, analog, and digital system and schematic drawings! Every stencil
symbol has been built to fit proportionally on the included A-, B-, and C-size drawing
page templates (or use your own page if preferred). Components are provided for
system block diagrams, conceptual drawings, schematics, test equipment, racks, and
more. Page templates are provided with a preset scale (changeable) for a good presentation
that can incorporate all provided symbols...
The
Josephson effect was predicted in 1962 by British physicist Brian David Josephson.
It postulated the possibility of a resistance-less path for electrical current across
an extremely thin insulator sandwiched between two superconductors. Dr. Juri Matisoo,
of IBM, is credited with building the first Josephson junction switch in 1967, demonstrating
sub-nanosecond switching times. Back in the day, superconducting materials, like graphene,
were resources available only to well-funded research establishments like major corporations,
universities, and government facilities. Now, anyone with an interest can order both...
Homepage
Archives for March 2023. Items on the RF Cafe homepage come and go at a pretty
fast rate. In order to facilitate fast page loading, I keep the size reasonable - under a megabyte (ebay, Amazon, NY Times, etc., are multiple
megabytes). New items are added at the top of the content area, and within a few
days they shift off the bottom. If you recall seeing something on the homepage
but now it is gone, fret not because many years I have maintained
Homepage Archives.
Upon completion of this chapter, you will
be able to: 1. State the applications of a
resonant circuit. 2. Identify the conditions that exist in a resonant circuit.
3. State and apply the formula for resonant frequency of an AC circuit. 4. State
the effect of changes in inductance (L) and capacitance (C) on resonant frequency
(fr). 5. Identify the characteristics peculiar to a series resonant circuit. 6.
Identify the characteristics peculiar to a parallel resonant circuit. 7. State and
apply the formula for Q. 8. State what is meant by the bandwidth of a resonant circuit
and compute the bandwidth for a given circuit. 9. Identify the four general types
of filters. 10. Identify how the series- and parallel-resonant circuit can be used
as a bandpass or a band-reject filter...
In 1970, engineers at the Hamilton Watch Company
introduced the world's first solid state electronic digital watch called the
Pulsar Time Computer. It went on sale commercially two years later, just a few months
after this article appeared in the December 1971 issue of Popular Electronics
magazine. Motorola created this "$25,000 Sundial," which represents the research and
development cost of the LED clock display that the company predicted would one day lead
to an inexpensive wristwatch. Maybe they hadn't seen the The Tonight Show
show where it made its debut in 1970. The Pulsar Big Time watch retailed for
$295 in 1972, which in 2018 is the equivalent of $1,777 (per the BLS Inflation
Calculator). That's about three times the cost of the top end Series 4 Apple
Watch today, and all the Pulsar watch could do was tell time...
For the sake of all the avid cruciverbalists
amongst us, each week I create a new
technology-themed crossword puzzle using only words from my custom-created
list related to engineering, science, mathematics, chemistry, physics, astronomy,
etc. At least 10 clues with an asterisk (*) in this technology-themed
crossword puzzle are pulled from the past week's (7/30 - 8/3) "Tech Industry Headlines"
column on the RF Cafe homepage. You will never find among the words names of politicians,
mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You
might, however, see someone or something in the exclusion list directly related
to this puzzle's theme, such as Hedy Lamar or the Bikini Atoll, respectively. Enjoy!...
Popular Electronics reader Frederic D.
Barber, Jr., was having none of the newfangled designations for standard
physical units as reported in the April 1966 issue. He, and evidently many others,
was not ready to accept the replacement of terms such as cycles per second (cps) with
Hertz (Hz), or seemingly any other change that included honoring a person by using his/her
name. We don't know whether...
The eleventh hour of the eleventh day of
the eleventh month - November 11th, at 11:00 am - that is when the armistice (cease
fire) began in 1918, unofficially ending World War I. This music video
Veteran's Day tribute is by Canadian citizen
Terry Kelly. It was written after an experience he had on Veterans Day in 1999.
Terry went blind at an early age, but has excelled as an athlete and a musician.
"A Pittance of Time" is done in the finest Celtic tradition. Per the U.S. Department
of Veteran Affairs website: "World War I – known at the time as 'The Great War'
- officially ended when the Treaty of Versailles was signed on June 28, 1919, in
the Palace of Versailles outside the town of Versailles, France. However, fighting
ceased seven months earlier when an armistice, or temporary cessation of hostilities,
between the Allied nations and Germany went into effect on the eleventh hour of
the eleventh day of the eleventh month. For that reason, November 11, 1918, is generally
regarded as the end of 'the war to end all wars...'" |