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Homepage Archive - February 2023 (page 4)

See Page 1 | 2 | 3 | 4 | of the February 2023 homepage archives.

Tuesday the 28th

What's Your EQ (Electronics Quotient)?

What's Your EQ (Electronics Quotient)?, April 1963 Radio-Electronics - RF Cafe"What's Your EQ?" (Electronics Quotient, a la IQ - Intelligence Quotient) was a feature run in Radio-Electronics magazine for a couple years in the early 1960's. It was a quiz for challenging your knowledge of basic electronic circuit functions. Most of them are relatively simple exercises in voltage division, resistor-capacitor (RC) and resistor-indictor (RL) time constants, resonant frequency, and transformer input/output ratios (voltage and/or current and/or power). Sometimes, the first step in solving the poser is to rearrange the schematic into a more familiar configuration. Also, read the wording carefully to determine whether parts of the circuit can be ignored. Answers are at the bottom of the page. Note that I do not agree with the magazine's answer for the "How Much Voltage?" circuit. My solution is presented below with the rest of the answers.

TINA-TI Spice-Based Circuit Simulator

TINA-TI Spice-Based Circuit Simulator (FREE) - RF CafeFor many years, Texas Instruments has offered a free Spice-based circuit simulator called TINA-TI. The UI is very intuitive and I use it fairly often. "TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages and waveforms. TINA's schematic capture is truly intuitive - a real 'quickstart.' We bet that you won't. TINA is a product of DesignSoft exclusively for Texas Instruments. This complimentary version is fully functional but does not support some other features available with the full version of TINA." Full commercial versions of TINA are available from DesignSoft beginning at around $160.

Gridless vs. Grid Vacuum Tubes

Gridless vs. Grid Vacuum Tubes (part 2), January 1937, Radio-Craft - RF CafeAssuming the 10 enumerated advantages of a gridless vacuum tube may be added to the 17 enumerated disadvantages of a gridded vacuum tube, there are 27 reasons, per author Henri Dalpayrat why one should consider abandoning the "old style" tubes for his revolutionary concept. Part 1 of this 2-part series discussed the unavoidably negative features of a gridded vacuum tube. Part 2, presently, extolls the wonders of a gridless vacuum tube. Chief among the features is the use of "compressor bar" elements that are situated parallel to the electron flow rather than in series with it. Another major difference is the cathode element running vertically up the center of the tube and the cathode wraps around it. If I had to draw a comparison of gridless versus gridded vacuum tubes with semiconductor devices, the former more closely relates to a field effect transistor (FET) and the latter to a bipolar junction transistor (BJT). I say that because the compressor bars' action on the electron flow is to change the concentration (density), effectively having the ability to cut off the current...

Quick and Efficient Color X-Ray Images

Quick and Efficient Color X-Ray Images - RF Cafe"A new technique produces X-ray images in colour quickly and efficiently using a specially-structured device called a Fresnel zone plate (FZP). The technique could have applications in nuclear medicine and radiology, as well in non-destructive industrial testing and materials analysis. X-rays are frequently used to determine the chemical composition of materials thanks to the characteristic 'fingerprint' of fluorescence that different substances emit when exposed to X-ray light. At present, however, this imaging technique requires focusing the X-rays and scanning the whole sample. Given the difficulty of focusing an X-ray beam down to small areas, especially with typical laboratory X-ray sources, this is a challenging task, making images time-consuming and expensive to produce. Single exposure and no need for focusing and scanning The new method, developed by Jakob Soltau and colleagues at the Institute for X-ray Physics..."

The Wavelength Factor - Part 2

The Wavelength Factor - Part 2, May 1952 QST - RF CafeIn this series, author Yardley Beers discusses propagation effects, modulation systems, and receiver techniques. Part 1 of this 3-part article entitled "Influence of the Antenna of the Choice of Wavelength for Best Communications," appeared in the February 1952 issue of the ARRL's QST magazine. This second part concerns "Propagation, Modulation, and Receivers." I have also posted Part 3, which subsequently appeared in the August 1952 edition. A particularly interesting topic included in this installment is that of using a form of pulse modulation in FM broadcasting in order to exploit the "capture effect" whereby a signal in the presence of noise will tend to suppress the noise. I don't think modern stations use that method, possibly because of incompatibility with stereo channels and data added for digital readouts...

RF Cascade Workbook

RF Cascade Workbook - RF Cafe RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed. An intro video takes you through the main features...

Many Thanks to San Francisco Circuits for Continued Support!

San Francisco CircuitsSF Circuits' specialty is in the complex, advanced technology of PCB fabrication and assembly, producing high quality multi-layered PCBs from elaborate layouts. With them, you receive unparalleled technical expertise at competitive prices as well as the most progressive solutions available. Their customers request PCB production that is outside the capabilities of normal circuit board providers. Please take a moment to visit San Francisco Circuits today. "Printed Circuit Fabrication & Assembly with No Limit on Technology or Quantity."

Monday the 27th

Servel (Gas-Powered Refrigerators): A Wartime Message

Servel, Inc. (Gas-Powered Refrigerators) A Wartime Message, March 23, 1942 Life - RF CafeServel is not a name that immediately comes to mind (and probably not at all) when thinking of companies who manufactured refrigerators or any other household appliances. However, they were rather prominent in the in the early 1940's when this "Wartime Message" appeared in a 1942 issue of Life magazine. So, too, was Crosley, a name which lives on today, and they still make refrigerators (manufactured by Westinghouse). Unique about Servel refrigerators was that they operated off of natural gas. It might seem strange that a cooling - even freezing - process can be accomplished via a flame, but such is the case. In fact, Melanie's parents had a gas-powered refrigerator and a gas-powered chest freezer at their house on a mountaintop in West Virginia, where they got free natural gas from a well a gas company operated from their property. But I digress... The motivation for posting this piece is that Servel was one of hundreds of American companies that spent some of their hard-earned their advertising money to promote the sacrificial efforts of fellow citizens (many of whom were former employees or relatives of current employees). It was a time when major companies were owned and run by patriotic Americans...

Preventing Intentional EMI - aka Sabotage

Preventing Intentional EMI, aka Sabotage - RF Cafe"IEMI from high-power microwave sources and EM pulses can generate significant threats to electronic systems in civil and infrastructure. Thus, inclusion of methods that recognize and reduce IEMI in designs is more critical than ever. Before we can define intentional electromagnetic interference (IEMI), which will also be referred to as 'sabotage' in this article, let's begin by characterizing electromagnetic waves. A mechanical wave can be defined as a vibration or disturbance in matter through some medium (such as a solid, liquid, gas, or plasma). Sound waves occurring in the air are mechanical waves. A changing magnetic field induces a changing electric field and vice versa - these two are linked. The two changing fields ultimately will form electromagnetic waves. Electromagnetic waves aren't like mechanical waves; they don't need a medium to propagate. Thus, electromagnetic waves have the ability to travel not just through air and solid materials, but through the vacuum of space as well..."

Grand Island Monitor Station

Grand Island Monitor Station, February 1932 Radio-Craft - RF CafeThe geographic center of the 48 contiguous (conterminous) states in America is located about 2.6 miles northwest of the center of Lebanon, Kansas (39° 50' N, 98° 35' W). That is about 85 miles from the FCC's (Federal Communication Commission) first central frequency monitoring station at Grand Island, Nebraska. I have driven by that spot a couple times while traveling on Interstate 80. Grand Island is probably not much bigger today than it was in 1932 when this story was published in Radio-Craft magazine, although it boasts being the state's 4th largest city (population 48,000). "Island" must have a different definition in Nebraska than in the rest of the world ;-) Because of its remoteness - 6 miles from town to minimize electrical noise - a diesel generator (chosen to eliminate ignition noise) was installed on-site to provide the necessary 3-phase, 240-volt power for equipment. Great care was taken to shield cables and motors and eliminate unnecessary metal structural components. Engineers who designed and operated this and other early monitoring stations had no previous data to reference. They were creating the standards and technical foundations on which future generations would build...

Attosecond Electron Pulses Shortest Ever

Attosecond Electron Pulses Shortest Ever - RF Cafe"The shortest electron pulses ever made in the lab have been claimed by researchers in Germany. By firing ultrashort laser pulses at a tungsten nanotip, the team created electron pulses just 53×10-18 seconds long and then characterized the pulses using a new technique. When a short, intense laser pulse is fired at a material it can cause the emission of an extremely short pulse of electrons. These electrons are then driven back into the material before re-emerging - a process that can provide important information about the material's properties. The challenge in doing such experiments is knowing how long the electron pulses are and characterizing the electrons that are emitted. Now, Eleftherios Goulielmakis and colleagues at the University of Rostock have developed a new technique to create and study ultrashort electron pulses. In their experiment, an intense laser pulse is fired at tungsten nanotip that is just 70 nm in diameter at its apex. This causes the emission of a pulse of electrons from the tip..."

Buick Sonomatic Auto Radio Schematic & Parts List

United Models 980744, 980745 Schematic & Parts List, January 1947 Radio News - RF CafeMagazines usually provided at least a brief description on the circuit functionality for each of the radio models presented in schematic format. The January 1947 issue of Radio News published schematics and parts lists for six sets, including this for the United models 980744 and 980745 "Sonomatic," but not a word about any of them accompanied it - just the schematic and PL. These are AM radios designed for Buick automobiles, and the series ran for more than a decade. One thumbnail image is the SAMS Photofact from an eBay auction, and the photo thumbnail is from an eBay auction. I post this type of information as part of my ongoing effort to make the information available to those who repair and/or restore vintage vacuum tube radio sets...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 16,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. 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.

Many Thanks for Alliance Test Equipment's Support!

Allied Test Equipment Products - RF CafeAlliance Test Equipment sells used / refurbished test equipment and offers short- and long-term rentals. They also offer repair, maintenance and calibration. Prices discounted up to 80% off list price. Agilent/HP, Tektronix, Anritsu, Fluke, R&S and other major brands. A global organization with ability to source hard to find equipment through our network of suppliers. Alliance Test will purchase your excess test equipment in large or small lots. Blog posts offer advice on application and use of a wide range of test equipment. Please visit Allied Test Equipment today to see how they can help your project.

Sunday the 26th

Electronics Theme Crossword Puzzle for February 26

Electronics Theme Crossword Puzzle for February 26, 2023 - RF CafeThis "X" marks the spot with this custom RF Cafe electronics-themed crossword puzzle for February 26th. It contains words and clues which pertain strictly to the subjects of electronics, mechanics, power distribution, engineering, science, physics, astronomy, chemistry, etc. If you do see names of people or places, they are directly related to the aforementioned areas of study. As always, you will find no references to numbnut movie stars or fashion designers. Need more crossword RF Cafe puzzles? A list at the bottom of the page links to hundreds of them dating back to the year 2000. Enjoy...

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...

Many Thanks to Reactel for Their Long-Time Support!

Reactel Filters - RF Cafe

Reactel has become one of the industry leaders in the design and manufacture of RF and microwave filters, diplexers, and sub-assemblies. They offer the generally known tubular, LC, cavity, and waveguide designs, as well as state of the art high performance suspended substrate models. Through a continuous process of research and development, they have established a full line of filters of filters of all types - lowpass, highpass, bandpass, bandstop, diplexer, and more. Established in 1979. Please contact Reactel today to see how they might help your project.

Friday the 24th

The Electronic Revolution

The Electronic Revolution, April 1963 Radio-Electronics - RF CafeAmongst the topics addressed in this "The Electronic Revolution" article in a 1968 issue of Radio-Electronics magazine is "thermoelectron cells that convert solar radiation into electric current at an efficiency of 86%." Having not seen the term before, but guessing it was based on a heating effect rather than a radiation effect, I looked it up and found thermoelectron is "a negative ion, or electron, emitted from a body at high temperature." That is akin to "thermionic" emission, such as what happens when a vacuum tube's heater element spews electrons. Such technology, along with the "Electronic Automated Revolution," "The Instant Newspaper," computers, and lasers are why editor Hugo Gernsback declares, "The Great Accomplishments of Electronics Are Still to Come..."

Please Thank RF & Connector Technology for Their Support

RF & Connector Technology - RF CafeProviding full solution service is our motto, not just selling goods. RF & Connector Technology has persistently pursued a management policy stressing quality assurance system and technological advancement. From your very first contact, you will be supported by competent RF specialists; all of them have several years of field experience in this industry allowing them to suggest a fundamental solution and troubleshooting approach. Coaxial RF connectors, cable assemblies, antennas, terminations, attenuators, couplers, dividers, and more. Practically, we put priority on process inspection at each step of workflow as well as during final inspection in order to actualize "Zero Defects."

What Wives Think About Ham Radio

What Wives Think About Ham Radio, December 1966 QST - RFCafeWhen I first saw the title "What Wives Think About Ham Radio" of this 1966 QST magazine article, I thought it was going to be a comical parody on how wives (YL's) of Ham radio operators (OM's) viewed their husbands' hobby. It turned out to be a report on a nationwide survey. Many of wives of Hams were themselves licensed operators which, at the time, required Morse code proficiency in addition to radio theory and regulations. In 1966 the average cost of a Ham shack layout was about $1,000, which is equivalent to $9,093 in 2023 dollars according to the BLS's Inflation Calculator. As with most electronics equipment, the quality and features have evolved significantly in the intervening decades, so you get a lot more capability for your investment today. If you believe the author presents results honestly, the general attitude was that wives would rather have their hubbies engaged in an educational at home or with like-minded men than at a bar or sporting event. A majority also thought that spending on Ham equipment activities was not at the expense of essential family needs...

Heat Circuits Move Temperature Like Current

Heat Circuits Move Temperature Like Current - RF Cafe"Can heat be channeled similar to how circuits control the flow of electricity? Possibly yes, according to a new study, if a new kind of quasiparticle could effectively be harnessed to make a practicable heat switch. Nearly every piece of technology today could be a case study in electricity being channeled toward productive purposes. With the right materials, heat could be made to be have like a different kind of current. However, says study senior author Joseph Heremans, a physicist and engineer at Ohio State University, 'Unlike electrical current, heat flows everywhere and is much harder to control.' Yet, even an imperfect heat switch could still have major technological impacts. For instance, more than 70 percent of the energy that humanity uses originates in heat, such as combustion engines. Heat switches can boost the efficiency of entire classes of heat engines, such as solar thermal power plants..."

Emerson Models 501, 502, 504 Schematic & Parts List

Emerson Models 501, 502, 504 Schematic & Parts List, November 1947 Radio News - RF CafeThis is the schematics and parts list set for vintage Emerson vacuum tube radio models 501, 502, and 504, as they appeared in the November 1947 issue of Radio News magazine. I scan and post these for the benefit of hobbyists and historians seeking such information. As time goes by, there is less and less likelihood that records of these relics from yesteryear's archives will be made available. To the left is the cover page for the Sam's PhotoFact data packet. To the lower right are example of the Emerson Model 502 that appeared on eBay at one time. As with all historical information, it takes someone with a personal interest in preserving the memories in order to fulfill the mission, and I am glad to be a small part of that cadre...

Post Your Engineer & Technician Job Openings on RF Cafe for Free

/jobs.htm">Engineering Job Board - RF CafeRF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable /jobs.htm">job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge. 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...

Many Thanks to Aegis Power Systems for Their Continued Support!

Aegis Power Systems - RF CafeAegis Power Systems is a leading supplier of AC-DC and DC-DC power supplies for custom and special applications. Aegis has been designing and building highly reliable custom power supplies since 1995. They offer a complete line of switch mode power supplies and power converters for a variety of markets including defense, industrial, aircraft, VME, and telecom. Supports military, aircraft, EV, telecom, and embedded computing applications. Design and manufacture of custom power supply solutions to meet each customer's exacting specifications. Please visit Aegis Power Systems today. Manufactured in the USA.

Thursday the 23rd

Transistor Substitution Box

Transistor Substitution Box, February 1960 Radio-Electronics - RF CafeThere aren't many people using transistor substitution boxes these days because circuit simulator software is readily available to reasonably predict which type will serve the intended purpose. However, back in 1960 when this article appeared in Radio-Electronics maga zine, substitution boxes for not just transistors, but also capacitors, resistors, and sometimes inductors were used quite often when prototyping and/or troubleshooting circuits. I used resistor and capacitor substitution boxes all the time in the early and mid 1980's while working as an electronics technician at Westinghouse Oceanic Division, in Annapolis, Maryland. That was my first place of employment after separating from the USAF. Prior to moving into the engineering lab, I built electronics assemblies for U.S. Navy sonars used on torpedoes, ship hulls, and towed vehicles, including printed circuit assemblies, cable harnesses, chassis assemblies, and piezoelectric transducers. Occasionally, I was tasked to build component substitution boxes for the engineering lab and the test equipment repair / calibration (metrology) group. Little did I know at the time that in the near future I would be using some of the equipment I built...

Chinese Spy Balloon View from U-2

Chinese Spy Balloon View from Fighter Jet - RF CafeYep, that's a Lockheed U-2 wingtip in that photo! That's 1955 technology (upgraded, of course), same year as the still-in-service B-52 Stratofortress. "The multi-ton payload that defense officials had claimed was attached to a Chinese spy balloon that floated across North America earlier this month looked like a oversized, suspended satellite, according to a photo released by the Pentagon on Wednesday. The image, taken from the cockpit of an Air Force U-2 spy plane, shows two large panels dangling from a balloon several times larger than the payload itself. 'The majority of the balloon, including the payload, was recovered,' Sabrina Singh, a Pentagon spokeswoman, said during a briefing Wednesday in which she confirmed the photo's authenticity. Defense officials said the surveillance equipment suspended from the balloon, which the Pentagon said earlier this month belonged to the Chinese government, was designed to spy on sensitive U.S. military sites. It resulted in a 1,500 square meter debris field after an Air Force F-22 shot it down off the coast of South Carolina..."

Identifying Windings of Salvaged Transformers

Identifying Windings of Salvaged Transformers, September 1956 Popular Electronics - RF CafeHere is an interesting article that was probably much needed in its day (1956 Popular Electronics magazine) when many hobbyists were building and repairing their own electronic equipment. Being able to measure and identify unknown transformer winding parameters is key to both troubleshooting and determining whether a particular transformer is applicable for your need. Even professional repair shops often scavenged transformers from scrapped chassis for use in equipment brought in for service. The process can be extended to multiple winding transformers. Now you, too, can confidently tackle the unknown transformer and determine its construction...

Quantic PMI February Product Announcement

Quantic PMI February 2023 Product Announcement - RF CafeQuantic PMI, a leading supplier of custom, high-reliability MIC/MMIC components and subsystems for applications in space, military, communications, commercial and consumer electronics systems for more than three decades, introduced six new products this month of February in their extensive line of RF and microwave components. Included amongst them are a 0.8 to 2.5 GHz two-way power divider; an absorptive, high speed, SP3T, absorptive switch for 8.0 to 12.0 GHz; a hybrid coupler with a frequency of 5.6 to 5.8 GHz; a highpass filter with a passband of 26.5 to 40.0 GHz; an absorptive, SP6T pin diode switch for 2.0 to 20.0 GHz; a switched filter bank with a frequency range of 30 to 600 MHz; and an absorptive, SP6T pin diode switch for 2.0 to 20.0 GHz...

Television-Themed Comics

Television-Themed Comics June 1949 Radio & Television News - RF CafeThe June 1949 issue of Radio & Television News magazine had four television-themed comics. Television at that time was a relatively new home appliance, so there was a huge amount of interest in the technology. It hadn't really been all that long since the public got used to hearing sound (aka "talkies") in the movie theater, so the mystique that surrounded television made it the subject of a lot of puns and jokes. 1949 was a mere four years after the end of World War II, and the post-war economic boom was primed by a surplus of left-over electronic components along with lots of available talent both in the areas of design and assembly. There is a growing list of other comics at the bottom of the page. Over time, I am colorizing many of them, as with these...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 16,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. 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.

Many Thanks to Berkeley Nucleonics for Continued Support!

Berkeley Nucleonics Corp - RF CafeBerkeley Nucleonics Corporation (BNC) is a leading manufacturer of precision electronic instrumentation for test, measurement, and nuclear research. Founded in 1963, BNC initially developed custom pulse generators. We became known for meeting the most stringent requirements for high precision and stability, and for producing instruments of unsurpassed reliability and performance. We continue to maintain a leadership position as a developer of custom pulse, signal, light, and function generators. Our designs incorporate the latest innovations in software and hardware engineering, surface mount production, and automated testing procedures.

Wednesday the 22nd

Holes and the Service Technician

Holes and the Service Technician, April 1963 Radio-Electronics - RF CafeIt is understandable if, based on this article's title, "Holes and the Service Technician," you thought maybe it had to do with semiconductors. Silicon was beginning to overtake germanium as the substrate of choice it appeared in a 1963 issue of Radio-Electronics magazine. Electron conduction seemed intuitive to most people involved in electronics; however, the concept of hole conduction caused a lot of head scratching. But, I digress. This article discusses how to create various types of holes in metal. It might seem like a no-brainer task, if you have ever needed to make precisely shaped and dimensioned holes in metal, you know it is not always such a simple task - especially in soft sheet metal. Achieving a truly round hole - especially of large diameter - in an aluminum chassis requires securely clamping the work piece to the table and using a sturdy drill press. Otherwise, you almost always get an oblong hole. A machinist at Westinghouse showed me one day back in the 1980's how he would get the chassis secured and drill press positioned, then place a couple layers of paper towel on the metal before lowering the drill bit onto the chassis. It helped fill the space between drill bit flutes to prevent it from "walking" before both sides of the bit had a bite on the metal. It works like magic, even when using a hand drill. To this day I still do that...

Thin-Film Copper Sandwich Transforming Electronics

Thin-Film Copper Sandwich Transforming Electronics - RF Cafe"As devices get smaller and more powerful, the risk of them overheating and burning out increases substantially. Despite advancements in cooling solutions, the interface between an electronic chip and its cooling system has remained a barrier for thermal transport due to the materials' intrinsic roughness. Sheng Shen, Professor in the Department of Mechanical Engineering at Carnegie Mellon University has fabricated a flexible, powerful, and highly reliable material to efficiently fill the gap. 'At first glance, our solution looks like any ordinary copper film, but under a microscope the novelty of our material becomes clear,' explained Lin Jing, PhD student. The material, composed of two thin copper films with a graphene-coated copper nanowire array sandwiched between, is extremely user-friendly. 'Other nanowires need to be in-situ grown where the heat is designed to be dissipated so that their application threshold and cost is high..."

Carl & Jerry: Geniuses at Work

Carl & Jerry: Geniuses at Work, June 1956 Popular Electronics - RF CafeIn typical Carl & Jerry style, the teen experimenters ("makers" or "DIYers" in contemporary lingo) spent another summer vacation day cobbling together an electromechanical contraption or even purely electronic device with a specific goal in mind. Whether designing and building a circuit for tracking down the cause of strangely acting synchronized wall clocks ("The Crazy Clock Caper") or devising a system for catching a vandal in the act of vandalizing ("Geniuses at Work" - this story), creator John T. Fry provides a mix of developing personalities, describing the task at hand, and maintaining a degree of suspense regarding how the adventure will end.

Please Thank IPP for Their Long-Time Support!

Innovative Power ProductsInnovative Power Products has been designing and manufacturing RF and Microwave passive components since 2005. We use the latest design tools available to build our baluns, 90-degree couplers, directional couplers, combiners/dividers, single-ended transformers, resistors, terminations, and custom products. Applications in military, medical, industrial, and commercial markets are serviced around the world. Products listed on the website link to detailed mechanical drawings, electrical specifications, and performance data. If you cannot find a product that meets your requirements on our website, contact us to speak with one of our experienced design engineers about your project.

Reconfigurable Antennas

Reconfigurable Antennas - RF Cafe"Reconfigurable antennas - those that can tune properties like frequency or radiation beams in real-time, from afar - are integral to future communication network systems, like 6G. But many current reconfigurable antenna designs can fall short: they dysfunction in high or low temperatures, have power limitations, or require regular servicing. To address these limitations, electrical engineers in the Penn State College of Engineering combined electromagnets with a compliant mechanism, which is the same mechanical engineering concept behind binder clips or a bow and arrow. They published their proof-of-concept reconfigurable compliant mechanism-enabled patch antenna today..."

Bayliss Transformers Advertisement

Bayliss Transformers Advertisement, March 9th The Wireless World - RF CafeThis advertisement for transformers, coils, chokes, and rotary converters from William Bayliss Ltd., on Sheepcoat Street in Birmingham, England, appeared in the March 9, 1932 edition of The Wireless World magazine. I only have this one edition, but will work on getting more soon. William Bayliss London Ltd. was a British manufacturer of scientific instruments, founded in London in 1919 by Sir William Maddock Bayliss, a well-known physiologist and Fellow of the Royal Society. The company specialized in the production of laboratory equipment, including microscopes, balances, and other precision instruments used in scientific research and education. One of the company's most significant contributions to science was the development of the Bayliss-Tate apparatus, a device used to measure the concentration of oxygen in blood. This instrument was based on the discovery made by Bayliss and his colleague, Ernest Starling, that the oxygen-carrying protein hemoglobin in blood changes color depending on the amount of oxygen it is carrying. The Bayliss-Tate apparatus was widely used in medical research and diagnosis for many years...

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith more than 1000 custom-built symbols, this has got to be the most comprehensive set of Visio Symbols available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Symbols are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing. The file format is XML so everything plays nicely with Visio 2013 and later...

Many Thanks to Amplifier Solutions Corporation (ASC) for Continuing Support!

Amplifier Solutions Corporation (ASC) - RF CafeAmplifier Solutions Corporation (ASC) is a manufacturer of amplifiers for commercial & military markets. ASC designs and manufactures hybrid, surface mount flange, open carrier and connectorized amplifiers for low, medium and high power applications using Gallium Nitride (GaN), Gallium Arsenide (GaAs) and Silicon (Si) transistor technologies. ASC's thick film designs operate in the frequency range of 300 kHz to 6 GHz. ASC offers thin film designs that operate up to 20 GHz. ASC is located in an 8,000 sq.ft. facility in the town of Telford, PA. We offer excellent customer support and take pride in the ability to quickly react to evolving system design requirements.

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