|
 Of all the ones to miss on this "Three
Letter Quiz," I screwed up drawing "A." It was a matter of thinking too hard
(at least that's my excuse). This is another of Robert P. Balin's many electronics-related
quizzes that appeared in Popular Electronics magazine over a couple of
decades. I will once again admonish non-old guys (unlike myself) to not spaz when
you see a vacuum tube in the circuit. Just mentally replace it with an equivalent
semiconductor device (a diode if it has two elements - other than a heater coil
- or a transistor if it has three or more elements). Surely, you will easily figure
our "A," and probably the other nine as well...
 Image response, harmonic of the IF, direct
IF response, harmonics of the oscillator, combination of the IF, heterodyne oscillator
radiation, cross modulation within the receiver, cross modulation external to the
receiver, same channel beat, adjacent channel beat and
monkey chatter are all sources of radio interference addressed
in this article that appeared in a 1946 edition of Radio News. I don't
know about you, but I've never heard of the term "monkey chatter." According to
the troubleshooting table it is, "Unintelligible modulation superimposed upon desired
station, having the character of 'inverted speech...
 "Engineers at the University of California,
Davis, have created a device capable of
producing mechanical energy at night by taking advantage of the warmth near
the ground and the extreme cold of outer space. This approach could support practical
uses such as moving air through greenhouses or other structures. The research was
recently published in the journal Science Advances. The device is based on a Stirling
engine, a type of machine that operates using temperature differences. According
to Jeremy Munday, professor of electrical and computer engineering at UC Davis and
co-author of the study, many engines, including internal combustion engines..."
 You can go into Walmart or Radio Shack (though
not for much longer) and pick up a pretty decent handheld
metal detector for under $100 these days, but in the 1950s even
a rudimentary metal detector was a rather large and heavy contraption. So unwieldy
were they that most had a belt clip and shoulder straps to help support and manipulate
them. That was the situation facing teen electronics aficionados
Carl and Jerry as they pondered how to leverage their combined
technical prowess to facilitate a thorough combing of the nearby Lake Michigan beach
area for treasures of coins, watches, jewelry, cigarette lighters, and other metallic
objects given up as lost by weekend seekers...
 If
you are relatively new to
radio control (R/C) operation, whether for the latest "drone"
craze (technically multi-rotor aircraft), model cars, model boats, helicopters,
or airplanes - or even robots, then you might be interested in discovering a little
about the systems which pioneers in the sport had to work with. In the mid 1950s
when this article appeared in Popular Electronics magazine, multi-rotors
and helicopters were not even in the list of model types. As with radios and television
sets, before the convenience and performance increase brought about by the advent
of solid state components, R/C modelers struggled with vacuum tube equipment, too.
If you are old enough to remember needing to re-tune your radio or TV occasionally
due to...
 The dawn of the "Space Race" was in the
late 1950s, when the USA and USSR were vying to be the first to place a satellite
in orbit around Earth, and then to see who could exploit the communications benefits
of those platforms most advantageously. At the same time, radio astronomy was gaining
ground quickly as gigantic new parabolic dishes were being constructed to "listen"
to signals from stars and hot, nebulous gases deep in space. Early concepts for
communications satellites did not very accurately predict what real-world satellites
would look like, as can be seen in this 1959 issue of Radio-Electronics
magazine's "What
New?" feature...
 I stopped creating the RF Cafe
engineering
and science themed crossword puzzles at the end of January in order to test
the interest in them. Although not much feedback has been received, enough came
in to motivate me to resume creating them. I actually enjoy making them, but it
can take up to an hour to make each crossword by the time I decide which version
to use, and then go through and manually format the images and text. Enjoy....
 "Scientists from the University of Warwick
and the National Research Council of Canada have set a new record by creating and
measuring the highest 'hole mobility' ever observed in a material that works with
standard silicon technology. Today's semiconductor devices are typically built from
Silicon (Si). As these components become increasingly compact and tightly packed,
they generate more heat and begin to approach fundamental performance limits.
Germanium (Ge), which appeared in some of the earliest transistors of the 1950s,
is gaining renewed attention as researchers look for ways to take..."
 Carl and Jerry were early adopters of the
near field communications (NFC) craze that is going full-swing today. The often harmlessly
mischievous teenage duo used their combined grasp of modern electronics to pull
off gags on unsuspecting friends... and sometime adversaries. In this episode, a
near-field transmitter and receiver pair is designed to help Carl bedazzle a scientist
who was attempting to disprove the ability to use extrasensory perception
(ESP) to determining what another person was thinking
about. In this case it was detecting which playing card was being displayed on an
overhead projector. Of course Carl didn't really have "the gift," but relied on
his co-conspirator, Jerry...
 Release 12.14.2025 of RF Cafe's amazing
Espresso
Engineering Workbook is now available for download. As always, it is provided
FREE of charge, compliments of my dedicated advertisers. The newest calculator translates
any text string into Morse code. I tried to get an audio output to work, but Excel
does not have a built-in sound generator, so the resulting noise it makes is really
awful; you would have hated it. You're welcome.
 It was not until 1963 that the International
Committee of Weights and Measures (CIPM) adopted the
cesium clock as the world scientific community's standard time
reference. It boasted an accuracy that kept it within 1.1 parts in 100 billion,
meaning it would not gain or lose more than a second in 3 thousand years. To show
how far technology has advanced since 1963, in April of 2014 the National Institute
of Standards and Technology (NIST) launched a new atomic clock called NIST-F2 (also
cesium-based) to serve as a new U.S. civilian time and frequency standard. NIST-F2
would neither gain nor lose one second in about 300 million years - a factor of
10 thousand. According to the U.S. Navy's official Time.Gov website, the Internet
time reported on my computer was 1 minute and...
 In his 1959 Radio-Electronics magazine
editorial, Hugo Gernsback envisioned a "National Facts Center" - a government-run
repository where all global scientific knowledge would be coded, cross-indexed,
and accessible via computers. He argued that researchers were drowning in uncoordinated
information, leading to wasted effort and redundant discoveries, like the "electronic
cigarette" concept which had been documented decades earlier. His solution anticipated
key aspects of the Internet: a centralized, searchable database that could deliver
relevant facts within seconds, drawn from worldwide sources. What he does not allow
for is the propensity for corrupt information - both intentional and not - to be
inserted into the system, thereby "poisoning the well...
 Long before there was Power Point, presentations
at training seminars were conducted using overhead projectors and larger-than-life
props of the devices being taught. The U.S. Navy, during World War II, set
up a special facility called the Visual Aid Model Shop located at
Radio Chicago, Chicago, Illinois. Its charter was to design and
build very large scale models of equipment and tools that service personnel used
while performing their duties. It is kind of funny to look at the sizes of some
of the items, like the 8x size radio chassis assembly shown in this article's main
photograph. As a life-long model builder myself, I would have loved to work in a
shop like that building torso-size electrolytic capacitors and potentiometer...
 Anatech Microwave Company (AMC) 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
models have been added to the product line in November, including a 1700-1900 MHz
directional coupler with a coupling of 20 ±0.5 dB, a 250 watt terminator
with frequency range from DC to 2.5 GHz, and a 2 dB SMA attenuator with
a frequency range...
 This advertisement from
Thordarson
is from one of my oldest editions of the American Radio Relay League's QST
magazine - December 1929. Thordarson Electric Manufacturing Company was founded
in Chicago, Illinois, by Chester H. Thordarson in 1895. He was the first producer
of industrial and commercial transformers. They are still in business today. Thordarson
patented more than 30 inventions for transformer design and manufacturing back in
its early days, including the still most popular form of laminations, the scrapless
"E and I." Many discussions are available on various transformer lamination configurations,
including the very common "E and I" types...
 News reports are full of features about
the wave of
radio controlled (R/C) "drones"
terrorizing citizens with their often inexperienced pilots navigating their camera-laden
craft to peer into bedroom windows, obtain "birds-eye" views of sporting events,
and to be a general pain in the posterior to people trying to enjoy their right
to privacy and safety (except, of course, unless it is the Government choosing to
violate them). Incredible advances in radio, navigation, and sensor systems has
facilitated a wide variety of very affordable multirotor (the correct term, not
"drone") aircraft that can literally fly themselves. For under $500 you can buy
a GPS-guided multirotor that can be programmed...
 Centric RF is a company offering from stock
various RF and Microwave coaxial
components, including attenuators, adapters, cable assemblies, terminations,
power dividers, and more. We believe in offering high performance parts from stock
at a reasonable cost. Frequency ranges of 0-110 GHz at power levels from 0.5-500
watts are available off the shelf. We have >500,000 RF and Microwave passive
components we can ship you today! We offer Quality Precision Parts, Competitive
Pricing, Easy Shopping, Fast Delivery. We're happy to provide custom parts, such
as custom cables and adapters, to fit your needs. Centric RF is currently seeking
distributors, so please contact us if interested. Visit Centric RF today.
 This 1959 Radio-Electronics magazine
article details a
transitional phase in PCB technology, where manufacturers were responding to
service technicians' concerns by implementing significant usability improvements.
Key features included color-coded conductors for circuit tracing, board-edge connectors
for easy removal, and "road-mapped" overlays replicating circuitry on the component
side. Innovations like Westinghouse's "See-Matic" board functioned as a built-in
schematic with component symbols printed directly on the conductor side. Boards
were single or double-sided, utilized wax coatings and solder-resist...
 "Q" is an often used term to describe the
electrical "quality" of a circuit or component, and for the most part anyone engaged
in the conversation (verbally or via reading) understands the concept. However,
having a firm grasp on the technical ramifications is required if you happen to
be a circuit or system designer and need to conform to certain specifications. "Q" can be good or bad, depending on your needs. If, for example,
you need a narrowband receiver to reject adjacent signals or you are designing a
high stability and spectrally clean oscillator, then you want all the "Q" you can
get. On the other hand, if your goal is to receive a spread spectrum signal or generate
white noise across...
 "The Heinz Nixdorf MuseumsForum (HNF), in
the city of Paderborn, Germany, occupies the former headquarters of the Nixdorf
Computer AG, the country's biggest computer builder of the 1970s and 1980s. Founded
in 1996, the HNF calls itself the largest computer museum in the world. HNF recently
opened a new gallery about
Silicon Valley and early microcomputers. In preparation for the gallery's opening,
some historical facts about the Valley and its name were researched for the HNF's
weblog. In 1977, West German newsmagazine Der Spiegel put 'Silicon Valley' in quotation
marks. It has since become a household name. Geographically, it refers..."
 For some reason the
subject of
grounding has been very prominent in my reading in the last few
days. The chapter I just finished reading in one of David Herres' books on the
National Electric Code (NEC) covering grounding of commercial and residential
services, an article by H. Ward Silver in QST titled, "Grounding and
Bonding Systems," and now this article by John T. Frye (of
Carl and Jerry fame) on grounding, makes for a wealth
of knowledge. Mr. Frye takes a unique approach at teaching by exploiting his gift
for story-telling. In this article, electronics repair shop owner Mac give technician
Barney a nice bit of tutelage on what constitutes a good Earth ground and what does
not. In some...
 New! Reset button
to put all user parameters at default values, streamlined
VBA code, updated Help, and more... For
more than two decades,
RF Cascade Workbook™ has been the de facto standard for spreadsheet-based
RF system cascade analysis. Chances are you have never used a spreadsheet quite
like this. Extensive use of VBA code enables complex calculations and automated
user interface features that make the experience more like a software program than
a spreadsheet. Using RF Cascade Workbook™ is as easy as any other Excel
spreadsheet, and it allows you to make modifications to the cells and charts if
your expertise is sufficient...
 Exodus Advanced Communications is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Power amplifiers ranging
from 10 kHz to 51 GHz with various output power levels and noise figure
ranges, we fully support custom designs and manufacturing requirements for both
small and large volume levels. decades of combined experience in the RF field for
numerous applications including military jamming, communications, radar, EMI/EMC
and various commercial projects with all designing and manufacturing of our HPA,
MPA, and LNA products in-house.
 "These pulses speed toward the moon at the
fantastic speed of light... through the ionosphere and on into the unknown void
surrounding the earth's atmosphere [emphasis added]." Hard as
it might be to imagine nowadays, in 1946 there was no empirical data regarding the
Earth's upper atmosphere other than the few instrumented sounding rockets that had
been launched for studies. Orbiting man-made communications satellites were still
a decade away when engineers at the Evans Signal Corps Engineering Laboratory in
New Jersey made the first
Earth-Moon-Earth (EME, aka 'moon bounce')
signal bounce using a massive radar and antenna that blasted 10 MW EIRP pulse
at the lunar surface. It was a big deal then; it's no big deal today. Amateur radio
hobbyists routinely conduct EME...
 It came as no surprise to amateur radio
operators that their operational privileges would be curtailed immediately after
the United States was drawn into World War II following the Japanese Imperial
Navy's attack on Pearl Harbor.
After all they were subject to the same kind of restriction during WWI. Just as
President Woodrow Wilson issued an executive order prohibiting unauthorized transmissions
by amateurs, President Roosevelt had the FCC ban the radio transmissions of Hams.
The fear was that enemy intelligence gathering posts would be able to divulge sensitive
information via "coded" broadcasts, as well as the unintentional providing...
 The electronics and communications worlds
were on fast-forward in 1959 when this "News
Briefs" column was published in Radio-Electronics magazine. Space exploration
featured Explorer VII's launch to study radiation belts with advanced instrumentation.
A pioneering "Stratovision" project planned airborne educational TV broadcasts across
six Midwestern states using DC-7 aircraft. Communications developments included
the world's most powerful naval transmitter in Maine for submarine communication
and Bell Labs' experiments with passive satellite balloons for intercontinental
microwave...
|
 • 700
Nokia Jobs Gone in Germany
• SSTV
Images Beamed from ISS to Celebrate 25 Years
• Manufacturing
down for 9th Month in November
• Regulatory
Standards
for EMC Compliance
• Murata Leads
RF Front-End Patent Race
 The
RF Cafe Homepage Archive
is a comprehensive collection of every item appearing daily on this website since
2008 - and many from earlier years. Many thousands of pages of unique content have
been added since then.
 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...
 As were the majority of
electronics-related comics from the 1950s and 1960s, this set of four from a
1963 issue of Radio-Electronics magazine had themes related to home entertainment
devices (radios, television, and stereos) and computers. Keep in mind that almost
all equipment used vacuum tubes rather than semiconductors. There was no such thing
as a home / personal computer then, either. The public was dealing with the introduction
and integration of computers into everyday life, so they (computers) were subject
to ridicule and criticism - legitimately. Those were the days where programs consisted
of cardboard "punched cards" that were placed in a stack into the computer, which
would "read" the presence or absence of rectangular holes as "0"s or "1"s. Most
used an 12 row by 80 column format, accommodating 80 words of 6 or 8 bits
each. Southern Senior High School, from which I graduated in 1976, had a small computer
which used punched cards...
 A few times in the past I have mentioned
the U.S. Army's long-running comic-book-style of training material for vehicle maintenance.
It began in 1940 under the title of The Army Motors and ran through the
end of World War II. In June 1951, at the beginning of the Korean War, the
publication was re-introduced as
PS Magazine - The Preventative Maintenance Monthly, where the "PS" part
stands for "Post Script," a la the "p.s." you might put at the end of a written
letter. In this case the "p.s." is a post script to the regular Army vehicle maintenance
manuals. I recently happened to run across the RadioNerds.com's extensive section
on PS Magazine, and it is a treasure trove of downloadable PDF versions of the magazines.
As you can see from the cover illustrations and the contents, its appeal was primarily
to the predominantly male vehicle maintenance force...
 This week's
crossword puzzle for October 9th sports an electronics theme. All RF Cafe crossword
puzzles are custom made by me, Kirt Blattenberger, and have only words and clues
related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry,
physics, and other technical subjects. As always, this crossword contains no names
of politicians, mountain ranges, exotic foods or plants, movie stars, or anything
of the sort unless it/he/she is related to this puzzle's technology theme (e.g.,
Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists
amongst us will appreciate the effort. Enjoy!
 In 1942 and throughout the War Years,
Life magazine (and many others) ran many articles promoting industries,
services, organizations, and individuals who contributed toward our ultimate victory.
Of course no one knew for certain that we would prevail in the end, but if it hadn't
turned out that way, it wouldn't have been for lack of effort and sacrifice. Part
of the objective was to inform the populace about how the country was pooling its
resources - physical, labor, and mental - to defeat the Axis Powers that sought
to takeover the world. This particular issue of Life focused on the
chemical industry, with the raw materials and processes used to produce needed
products both for fuel and for the base components of other finished goods. Sulphur,
potassium, and coal mining and processing, along with petroleum, common table salt,
and air and water were some of the most fundamental ingredients of every other item
needed to aid the effort. Ever hear of Ameriopl rubber?
 This is the first article I have posted from a
magazine called, simply, Electronics. It is very different from all the other
vintage electronics magazines I have used in the past. Electronics is much more
focused on military, space, and fundamental research. New issues were published bi-weekly
by McGraw-Hill from 1930 until 1988. About half the editions (this is not one of
them) had two to three times as many pages as the other half, with most of the extra
pages being advertisements. The publishers must have made a fortune on advertising revenue.
My guess is that the vast majority of the companies appearing in the early 1960s issues
I bought on eBay do not exist anymore, having either gone out of business or having been
acquired by bigger...
 Here is your custom made
Microwaves Themed Crossword Puzzle for July 31st, 2022. All RF Cafe crossword
puzzles are custom made by me, Kirt Blattenberger, and have only words and clues
related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry,
physics, and other technical subjects. As always, this crossword contains no names
of politicians, mountain ranges, exotic foods or plants, movie stars, or anything
of the sort unless it/he/she is related to this puzzle's technology theme (e.g.,
Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists
amongst us will appreciate the effort. Enjoy!
 This is another of the articles written
about
Lee de Forest that appeared in the January 1947 issue of Radio-Craft
magazine, in celebration of the 40-year anniversary since the industry-changing
Audio vacuum tube was invented. Author George H. Clark, a member of the first "radio-man"
to be graduated from the Massachusetts of Technology (MIT), was, in addition to
working for Marconi Wireless Telegraph Company, RCA, and the Telegraph and Telephone
Company, the U.S. Navy's "Sub-inspector of Wireless Telegraph Stations." He dealt
extensively with de Forest regarding installation and operation of radio systems
both on ships and on shore. Interestingly, he mentions that the first Audions were
used as detectors more so than as signal amplifiers, which in fact was de Forest's
original goal (a more sensitive detector) in his experimentation...
 A timeless introduction for newcomers to electronics,
this article in the 1954 Popular Electronics - the very first issue - presents
the basics of
what a capacitor is and how it works. As you might expect in a premier edition
of an electronics hobbyist magazine, a lot of fundamental information was introduced
over a wide range of topics including resistor and capacitor color codes, neon bulbs,
televisions, radio control model airplanes, amateur radio, home-built electronics
projects, electronic products kit building, model trains, stereo hi-fi equipment,
solar cells, and more. Popular Electronics pretty much stayed that course
for the first decade, and then began to adjust content to address new technologies...
 Punch cards have been used in computer systems
since the very early days of digital programming. They were probably the first form
of read-only memory (ROM), come to think of it. I hate to have to admit it, but
the meager computer used in my high school computer lab (circa early-mid 1970s)
used
punched cards. I never took the class, but stories abounded of how pranksters
would shuffle a stack of punch cards while the student programmer wasn't watching
and then get a good laugh when nothing worked. There are also plenty of cases where
a stack was inadvertently knocked onto the floor and had to be laboriously re-ordered.
IBM is the brand that comes to most people's minds when thinking about the old punched
card computer systems, but other companies like NCR (National Cash Register), HP
(Hewlett-Packard), DEC (Digital Equipment Corporation), and plenty of others others...
 In December of 1931, the discovery of deuterium
(aka "heavy water") was announced by Harold Urey, Japan abandoned the gold standard,
the New York Metropolitan Opera broadcasted an entire opera over radio for the first
time (on Christmas day), and the ARRL's QST magazine published an article
about how to improve a receiver by using a
screen-grid coupling stage on vacuum tubes. A "tickler coil" is introduced via
a tuned circuit to provide a small amount of positive feedback to the grid in order
to make the amplifier stage more sensitive in the band of interest. Care needed
to be taken to avoid so much feedback that oscillations could occur. As with most
of these old articles I post, while the exact application might not be relevant
in today's world of electronics, the basic principles are certainly timeless...
 As the planet's population grows older and
people have an increasing amount of disposable income and spare time, the opportunity
to engage in nostalgic endeavors has gone up. That includes
collecting, restoring, and operating equipment and peripherals that were the
mainstay of their lives during their halcyon days of youth. In recognition of the
new marketing opportunities, industries are popping up to feed the frenzy. Look
no farther than eBay and the amount of vintage items available for purchase - at
ever increasing prices. Having myself been an eBay buyer of memorabilia from my
early model airplane, model rockets, and electronics hobbies, I have watched prices
soar in many cases. Turntables (aka phonographs, or for the lowbrow types, record
players) are being manufactured again...
 Here
is a reprint of an article I had published in Wireless Design & Development
magazine in 1995. Some of the references are a bit dated, but the info is all still
very useful. Waypoint Software is now RF Cafe, and TxRx Designer is now Shareware
by the name of RF Workbench. With the advent of high speed personal computers, a
very insightful graphical method of determining inband mixer spurious products has
been largely forgotten. The
Spur Web™
(my name trademark, but used widely w/o attribution) chart rapidly identifies both
inband and out-of-band spurs, affording a pictorial view of where conversion system
frequencies lie with respect to all spur products. A comparison will be presented
between the Spur Web chart method and the common numerical method...
 Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 visits each
weekday. RF Cafe
is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 17,000 pages in the Google search index, RF Cafe returns in
favorable positions on many types of key searches, both for text and images.
Your Banner Ads are displayed on average 225,000 times per year! New content
is added on a daily basis, which keeps the major search engines interested enough
to spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. If you need your company
news to be seen, RF Cafe is the place to be...
 "Praetersonic" - now that's a word you don't
run up against very often. It is a combination of praeter* (beyond) and sonic (related
to sounds), or what more familiarly is called ultrasonic. If fact, praetersonics
was the early term given to
surface acoustic wave (SAW) piezoelectric devices. Amazingly,
even as far back as the early 1970s, SAW filters were being fabricated that
worked in the 40 MHz realm. This Popular Electronics article does a really nice
job of introducing the basics of SAW and BAW (bulk acoustic wave) technology at
the time it was coming into the mainstream. Lots of hurdles still needed to be
overcome, like high insertion loss, difficult to control impedances and internal
signal reflections, etc. As with many new technologies, pundits cast hopeful
prediction...
 I and many people who visit RF Cafe tend
to do our own
repair and maintenance work whenever possible. Having had this
obsession for as long as I can remember, there is no doubt that the ready availability
of service information and how-to aids available on the Internet not only makes
the job easier, but also makes things possible that could never have been achieved
a couple decades ago. When I needed to put new rotors and brakes on my 2011 Jeep
Patriot last month, a quick search turned up multiple videos of people demonstrating
how to do it. Sure, I've done dozens of brake jobs and am fairly comfortable with
what might be involved, but being able to watch a beginning-to-end video before
diving into it is really nice. My trusty Hanes repair manual was on-hand, but a
couple black and white photos and terse instructions usually do not describe the
complete environment. A couple years ago when my gas-fired furnace would light and
cut off after a few seconds, an Internet search turned up the likely cause...
 Even if you no longer - or never did - have
the need to wind your own
audio frequency output impedance matching transformers, this article from a
1970 issue of Popular Electronics magazine provides good insight into the factors
necessary for consideration when doing so. One particularly nice feature here is
that power handling is taken into account, including wire size to use for the primary
and secondary (or multiple outputs). At audio frequencies, where the transformer
is driving speakers with typical impedances of 4, 8, or 16 ohms, you do not need
to worry too much about parasitic capacitance and inductance. The basic equations
do a pretty good job of predicting performance. Author Ed Francis explains how to
modify a junk-box laminated core transformer to work, as well as providing a table
of enameled wire size ampacities and turns per linear inch. An example of how to
perform all the steps is given...
 Good, clean humor has always been a welcome
addition to my day whether it comes in the form of a printed comic strip, a TV show,
or someone's mouth. My father's side of the family was populated with many jokesters
who could be counted on to deliver an ad hoc pun or zinger at the appropriate moment.
The environment instilled a great appreciation for such entertainment, so these
electronics-themed comics that appeared in editions of Radio-Electronics,
Popular Electronics, et al, are a refreshing distraction from the workaday
world. An old saying claims "laughter is the best medicine," and while it cannot
cure cancer, a good dose of humor often helps ease the pain... |
