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Learn more - CREATE AN ACCOUNTSIGN IN JOIN IEEESIGN IN Close Access Thousands of Articles -- Completely Free Create an account and get exclusive content and features: Save articles, download collections, and talk to tech insiders -- all free! For full access and benefits, join IEEE as a paying member. CREATE AN ACCOUNTSIGN IN Consumer ElectronicsTopicMagazineTypeFeature The Inner Beauty of Basic Electronics Open Circuits showcases the surprising complexity of passive components Eric Schlaepfer Windell H. Oskay 6h 5 min read Blue [svg] Eric Schlaepfer was trying to fix a broken piece of test equipment when he came across the cause of the problem--a troubled tantalum capacitor. The component had somehow shorted out, and he wanted to know why. So he polished it down for a look inside. He never found the source of the short, but he and his collaborator, Windell H. Oskay, discovered something even better: a breathtaking hidden world inside electronics. What followed were hours and hours of polishing, cleaning, and photography that resulted in Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022), an excerpt of which follows. As the authors write, everything about these components is deliberately designed to meet specific technical needs, but that design leads to "accidental beauty: the emergent aesthetics of things you were never expected to see." From a book that spans the wide world of electronics, what we at IEEE Spectrum found surprisingly compelling were the insides of things we don't spend much time thinking about, passive components. Transistors, LEDs, and other semiconductors may be where the action is, but the simple physics of resistors, capacitors, and inductors have their own sort of splendor. High-Stability Film Resistor A photo of a high-stability film resistor with the letters "MIS" in yellow. All photos by Eric Schlaepfer & Windell H. Oskay This high-stability film resistor, about 4 millimeters in diameter, is made in much the same way as its inexpensive carbon-film cousin, but with exacting precision. A ceramic rod is coated with a fine layer of resistive film (thin metal, metal oxide, or carbon) and then a perfectly uniform helical groove is machined into the film. Instead of coating the resistor with an epoxy, it's hermetically sealed in a lustrous little glass envelope. This makes the resistor more robust, ideal for specialized cases such as precision reference instrumentation, where long-term stability of the resistor is critical. The glass envelope provides better isolation against moisture and other environmental changes than standard coatings like epoxy. 15-Turn Trimmer Potentiometer A photo of a blue chip A photo of a blue chip on a circuit board. It takes 15 rotations of an adjustment screw to move a 15-turn trimmer potentiometer from one end of its resistive range to the other. Circuits that need to be adjusted with fine resolution control use this type of trimmer pot instead of the single-turn variety. The resistive element in this trimmer is a strip of cermet--a composite of ceramic and metal--silk-screened on a white ceramic substrate. Screen-printed metal links each end of the strip to the connecting wires. It's a flattened, linear version of the horseshoe-shaped resistive element in single-turn trimmers. Turning the adjustment screw moves a plastic slider along a track. The wiper is a spring finger, a spring-loaded metal contact, attached to the slider. It makes contact between a metal strip and the selected point on the strip of resistive film. Ceramic Disc Capacitor A cutaway of a Ceramic Disc Capacitor A photo of a Ceramic Disc Capacitor Capacitors are fundamental electronic components that store energy in the form of static electricity. They're used in countless ways, including for bulk energy storage, to smooth out electronic signals, and as computer memory cells. The simplest capacitor consists of two parallel metal plates with a gap between them, but capacitors can take many forms so long as there are two conductive surfaces, called electrodes, separated by an insulator. A ceramic disc capacitor is a low-cost capacitor that is frequently found in appliances and toys. Its insulator is a ceramic disc, and its two parallel plates are extremely thin metal coatings that are evaporated or sputtered onto the disc's outer surfaces. Connecting wires are attached using solder, and the whole assembly is dipped into a porous coating material that dries hard and protects the capacitor from damage. Film Capacitor An image of a cut away of a capacitor A photo of a green capacitor. Film capacitors are frequently found in high-quality audio equipment, such as headphone amplifiers, record players, graphic equalizers, and radio tuners. Their key feature is that the dielectric material is a plastic film, such as polyester or polypropylene. The metal electrodes of this film capacitor are vacuum-deposited on the surfaces of long strips of plastic film. After the leads are attached, the films are rolled up and dipped into an epoxy that binds the assembly together. Then the completed assembly is dipped in a tough outer coating and marked with its value. Other types of film capacitors are made by stacking flat layers of metallized plastic film, rather than rolling up layers of film. Dipped Tantalum Capacitor A photo of a cutaway of a Dipped Tantalum Capacitor [svg] At the core of this capacitor is a porous pellet of tantalum metal. The pellet is made from tantalum powder and sintered, or compressed at a high temperature, into a dense, spongelike solid. Just like a kitchen sponge, the resulting pellet has a high surface area per unit volume. The pellet is then anodized, creating an insulating oxide layer with an equally high surface area. This process packs a lot of capacitance into a compact device, using spongelike geometry rather than the stacked or rolled layers that most other capacitors use. The device's positive terminal, or anode, is connected directly to the tantalum metal. The negative terminal, or cathode, is formed by a thin layer of conductive manganese dioxide coating the pellet. Axial Inductor An image of a cutaway of a Axial Inductor A photo of a collection of cut wires Inductors are fundamental electronic components that store energy in the form of a magnetic field. They're used, for example, in some types of power supplies to convert between voltages by alternately storing and releasing energy. This energy-efficient design helps maximize the battery life of cellphones and other portable electronics. Inductors typically consist of a coil of insulated wire wrapped around a core of magnetic material like iron or ferrite, a ceramic filled with iron oxide. Current flowing around the core produces a magnetic field that acts as a sort of flywheel for current, smoothing out changes in the current as it flows through the inductor. This axial inductor has a number of turns of varnished copper wire wrapped around a ferrite form and soldered to copper leads on its two ends. It has several layers of protection: a clear varnish over the windings, a light-green coating around the solder joints, and a striking green outer coating to protect the whole component and provide a surface for the colorful stripes that indicate its inductance value. Power Supply Transformer A photo of a collection of cut wires A photo of a yellow element on a circuit board. This transformer has multiple sets of windings and is used in a power supply to create multiple output AC voltages from a single AC input such as a wall outlet. The small wires nearer the center are "high impedance" turns of magnet wire. These windings carry a higher voltage but a lower current. They're protected by several layers of tape, a copper-foil electrostatic shield, and more tape. The outer "low impedance" windings are made with thicker insulated wire and fewer turns. They handle a lower voltage but a higher current. All of the windings are wrapped around a black plastic bobbin. Two pieces of ferrite ceramic are bonded together to form the magnetic core at the heart of the transformer. From Your Site Articles * Dell Tried to Hide Bad Capacitors Problem 2003-2005 > * Hands On - IEEE Spectrum > * Watch: Laser Origami Makes Inductors > Related Articles Around the Web * Open Circuits: The Inner Beauty of Electronic Components: Oskay ... > * Open Circuits | No Starch Press > * Open Circuits > passive componentsArt of Electronicsresistorscapacitorsinductorsbooks {"imageShortcodeIds":[]} Eric Schlaepfer Eric Schlaepfer runs the popular engineering Twitter account @TubeTimeUS, where he posts cross-section photos, shares his retrocomputing and reverse engineering projects, investigates engineering accidents, and even features the occasional vacuum tube or two. He is coauthor of Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022). Windell H. Oskay Windell H. Oskay is the cofounder of Evil Mad Scientist Laboratories, where he designs robots for a living. He is coauthor of Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022). The Conversation (0) A robot suspended by red cables holding a drumstick descends towards a cymbal in a dramatically lit warehouse Video Friday: Robots at Night 13 Jan 2023 3 min read A white rocket, seen from below as it launches into the sky AerospaceTopicTypeRoboticsNews Relativity Space Aims for Orbit 13 Jan 2023 4 min read Closeup of fingers pinching a thin white rectangle which has 3 black rounded rectangles inset Consumer ElectronicsTopicTypeNews Paper Batteries, Blue Quantum Dots, and Other Enabling Technologies from CES 2023 12 Jan 2023 3 min read The InstituteTopicArticleTypeHistory of Technology How This Record Company Engineer Invented the CT Scanner The machine, made to image the human brain, won him a Nobel Prize Joanna Goodrich Joanna Goodrich is the associate editor of The Institute, covering the work and accomplishments of IEEE members and IEEE and technology-related events. She has a master's degree in health communications from Rutgers University, in New Brunswick, N.J. 12 Jan 2023 4 min read black and white image of a man in a suit standing next to a large x-ray machine Research engineer Godfrey Hounsfield invented the CT scanner to create three-dimensional brain images. PA Images/Getty Images ieee historyieee tech historyhistory of technologyct scannermedical devicesieee milestonetype:ti The inspiration for computed tomography (CT) came from a chance conversation that research engineer Godfrey Hounsfield had with a doctor while on vacation in the 1960s. The physician complained that X-ray images of the brain were too grainy and only two-dimensional. Hounsfield worked at Electrical and Musical Industry in Hayes, England. Best known for producing and selling Beatles records, EMI also developed electronic equipment. When Hounsfield returned to work after that vacation, he proposed a project to his supervisor to develop a machine that could create three-dimensional brain images. The machine would project narrow beams of X-rays through a person's head, and a computer would use the resulting data to construct a series of cross-sections that together would represent the brain in 3D. Hounsfield worked with neuroradiologists to build the machine, and in 1971 they produced the first computed tomography scan of a human brain. CT scans are now used to pinpoint the location of blood clots, tumors, and bone fractures. For his invention, Hounsfield was named corecipient of the 1979 Nobel Prize in Physiology or Medicine. Hounsfield's scanner was commemorated with an IEEE Milestone during a ceremony held on 26 October at the EMI Old Vinyl Factory, in Hayes, England, where the technology was developed. The IEEE United Kingdom and Ireland Section sponsored the nomination. Selling Beatles albums and developing medical equipment After the X-ray machine was invented in 1896, it quickly became standard equipment in hospitals. The machines produce great images of bones because their dense structures absorb X-ray beams well. The absorption pattern makes the bones look white on film. But soft-tissue organs such as the brain looked foggy because the radiation passed through them. While Hounsfield served with the Royal Air Force, he learned the basics of electronics and radar. In 1951 he joined EMI, where he developed guided weapon systems and radar. His interest in computers grew, and in 1958 he helped design the Emidec 1100--the first commercially available all-transistor computer made in Britain. After that project, Hounsfield's supervisor warned him that his job would be in jeopardy if he didn't come up with another good idea. Hounsfield thought back to the conversation with the doctor about the limitations of X-ray images, then he proposed the project that would become the CT scanner. EMI didn't develop or manufacture medical equipment and wasn't interested in getting into that line of business, but Hounsfield's supervisor believed in his idea and approved it. The company couldn't fully fund the project, so Hounsfield applied for and received a grant of around US $40,000--approximately $300,000 in 2022 figures--from the British Department of Health and Social Care. A CT scanner for cow brains and human ones Hounsfield worked with neuroradiologists James Ambrose and Louis Kreel to build the first prototype. It was small enough to sit atop a table. They tested the machine on small pigs, and after successfully producing images of their brains, the three men built a full-size scanner. The CT scanner was first tested on human brains preserved in formalin. But the brains weren't ideal because the chemical had hardened their tissues so severely that they no longer resembled normal brain matter, as described in an article about the scanner in The Jewish News of Northern California. Because the scanner was intended for use on living patients, Hounsfield and his team looked for a brain similar to a human's. They procured fresh cow brains, but those couldn't be used because an electric shock was used to stun the animals before they were slaughtered. The procedure caused the brain to fill with blood, and the fluid obstructed the radiologists' view of the organ's structure. Ambrose, who was part Jewish, suggested using kosher cow brains because instead of being stunned, the animals had their jugular slit. The process drained blood away from the skull--which enabled clear CT scans of the brain. After several successful tests, the machine was ready to be tried on a human. The scanner was installed in 1971 at Atkinson Morley Hospital, in London, where Ambrose worked. The first patient was a woman who showed signs of a brain tumor. She lay on a table as X-rays were shot through her skull from a single site above her head. The beams passed through her and struck a crystal detector housed in the gantry below her head. Both the X-ray source and the detector moved around her in 1-degree increments until they had turned 180 degrees, with each device ending up at the other one's starting point. That allowed the scanner to depict the brain in individual layers. Hounsfield described it as putting the brain "through a bacon slicer," according to an article about the scanner on the Siemens MedMuseum website. The detector recorded the X-ray signals and sent the data to a computer. The computer constructed an image of the brain using physicist Allan MacLeod Cormack's algebraic reconstruction technique. The technique built up an image by filling in a matrix, each square of which corresponded to a part of the examined organ, according to a Nobel news release about the scanner. Because the crystal detector was 100 times more sensitive than X-ray film, the density resolution was much higher, making the resulting image much clearer. Cormack shared the 1979 Nobel Prize with Hounsfield. The scan took 30 minutes and the computerized construction of the image took another two hours. The image showed a cystic mass about the size of a plum on the patient's left frontal lobe. EMI began manufacturing CT scanners and sold them to hospitals with success. But within five years, General Electric, Siemens, and other companies began making more enhanced, full-body scanners. EMI eventually stopped producing its scanners because it couldn't compete with the other manufacturers. Administered by the IEEE History Center and supported by donors, the Milestone program recognizes outstanding technical developments around the world. The CT scanner's Milestone plaque, which is displayed on an exterior wall at the Old Vinyl Factory, reads: On 1 October 1971, a team at the EMI Research Laboratories located on this site produced an image of a patient's brain, using the world's first clinical X-ray computerized tomography scanner, based on the patented inventions of Godfrey Hounsfield. The practical realization of high-resolution X-ray images of internal structures of the human body marked the beginning of a new era in clinical medicine. From Your Site Articles * The Women Behind ENIAC > * Path Found to a Combined MRI and CT Scanner > * The Superconducting Shields Behind MRIs' Triumph > Keep Reading |Show less Consumer ElectronicsTopicTypeComputingSponsored Article Building the Future of Smart Home Security Engineers must invent new technology to enhance security products' abilities Nate Wilfert Nate Wilfert is Vice President of Software Engineering at SimpliSafe. 22 Mar 2022 4 min read One engineer peers into a microscope to work on a small circuit while another engineer looks on In this article, SimpliSafe's VP of Software Engineering discusses his team's focus on creating a safer future through enhanced technology. SimpliSafe smart homeiotconnected homesecuritysimplisafe This is a sponsored article brought to you by SimpliSafe. It's nearly impossible to find a household today that doesn't have at least one connected smart home device installed. From video doorbells to robot vacuums, automated lighting, and voice assistants, smart home technology has invaded consumers' homes and shows no sign of disappearing anytime soon. Indeed, according to a study conducted by consulting firm Parks Associates, smart home device adoption has increased by more than 64 percent in the past two years, with 23 percent of households owning three or more smart home devices. This is particularly true for devices that provide security with 38 percent of Americans owning a home security product. This percentage is likely to increase as 7 in 10 homebuyers claimed that safety and security was the primary reason, after convenience, that they would be seeking out smart homes, according to a report published by Security.org last year. As the demand for smart home security grows, it's pertinent that the engineers who build the products and services that keep millions of customers safe continue to experiment with new technologies that could enhance overall security and accessibility. At SimpliSafe, an award-winning home security company based in Boston, Mass., it is the pursuit of industry-leading protection that drives the entire organization to continue innovating. In this article, Nate Wilfert, VP of Software Engineering at SimpliSafe, discusses the complex puzzles his team is solving on a daily basis--such as applying artificial intelligence (AI) technology into cameras and building load-balancing solutions to handle server traffic--to push forward the company's mission to make every home secure and advance the home security industry as a whole. Using AI to enhance safety and customer experience Since its founding in 2006, SimpliSafe has been reimagining antiquated security products and services and developing accessible technology that can be easily installed into homes across the country. It redefined the home security space by introducing wireless, DIY products and pioneered giving customers the ability to monitor their homes via a smartphone app. Today, SimpliSafe's talented engineering team continues to innovate by investigating how AI can be used to reduce false alarms and enhance the customer experience. False alarms are a constant obstacle in the home security and emergency response industries. Not only are false alarms annoying to customers, but they also make it difficult for emergency responders to differentiate between real emergencies and accidental alarm trips, which in turn, result in slower response times. One of our engineering team's top priorities is understanding how they can reduce false alarms and send help fast to address verified emergencies. The potential solution? Integrating AI into security cameras. Our engineering team is developing AI that will make our cameras "smarter" and give them the ability to identify specific objects to reduce false alarms and enhance the customer experience. Imagine having an outdoor camera that could tell you if the vehicle in your driveway is a friend, a stranger, or a police car. Or what about having a video doorbell that could tell you if the backpacked teenager on your front stoop is your daughter returning home from school or a delivery person dropping off tonight's takeout dinner? Customers are only interested in receiving alerts for movements that are out of the ordinary and security monitoring centers are only interested in addressing emergency events. Thanks to AI, we're on our way to addressing all of these needs. Currently, our engineering team is developing AI that will make our cameras "smarter" and give them the ability to identify specific objects with the ultimate goal of delivering a best-in-class customer experience. With these advanced cameras, customers will receive tailored app alerts detailing the specifics of the detected camera activity. In time, emergency operators will only receive calls for activity that appears out of the ordinary, thereby reducing false alarms and accelerating emergency response. As AI technology develops and as our engineering team grows, we can explore more ways AI can make SimpliSafe smarter, faster, simpler and more accurate to help us advance the future of security. There is still plenty to be uncovered and our engineers have a unique opportunity to create life-saving products and services that have a truly positive impact on the customer. Building infrastructure to meet the demand of a growing customer base Today, SimpliSafe has over 1 million subscribing customers and nearly 5 million connected devices working hard to protect homes against intruders, fires, water damage, and more. Managing the server activity of those connected devices is a unique challenge to SimpliSafe. Few companies come close to SimpliSafe's connected device volume. Due to the large volume, we move beyond what any major cloud provider can handle. Even the biggest international SaaS providers running on common cloud solutions only support a few hundred thousand devices at a given time. Given the lack of scalable cloud providers, we must turn to our engineers to create a solution that can scale as our customer base grows and ensure customers' servers are always operating smoothly, without interruption. To add to the challenge, most internet of things (IoT) companies use servers for "request and response," meaning that the connection used to first understand a customer's request and then provide them with a response is short-lived. SimpliSafe works differently. Unlike other IoT companies, we must keep long-lived connections for our backend servers. Constant connection between the customer and the server is crucial because it allows us to trace an alert back to a relevant customer and notify them of an emergency quickly, a task that would take too long if we used "request and response" protocol. Careers at SimpliSafe SimpliSafe logo If you are interested in learning more about SimpliSafe's engineering team and the technical problems they're looking to solve across software, hardware, firmware, mechanical, electrical, artificial intelligence, and cloud disciplines please visit SimpliSafe's career page. As an award-winning home security company, we understand better than anyone how important it is for a customer in a potentially dangerous situation to receive help swiftly. Not only do our engineers need to create a solution to manage our servers, but they must also create a solution that can load-balance with ease and provide a highly responsive experience for our customers. Thankfully, our talented team has created new and innovative technologies that are able to control all our servers as well as the data it processes. But load-balancing maintenance is an ongoing focus. We are always looking to hire more engineers who can help us scale to address our growing customer base. SimpliSafe's engineers are leading a growing number of innovative projects, more than can be outlined here. They span the gamut of advanced technology and engineering, including the development of new hardware devices, cameras, imaging technology, app development, cloud computing, cyber security protection, motion detection and user authentication technologies. No matter what our engineers are focused on, all are dedicated to enhancing safety. It's our mission to make every home secure that pushes us forward and challenges us to reimagine a safer world, achieved with the help of exceptional home security products. Related Articles Around the Web * SimpliSafe Careers: Home > * SimpliSafe > * SimpliSafe Home Security Systems | Wireless Home Security Alarms > Keep Reading |Show less Trending Stories The most-read stories on IEEE Spectrum right now TelecommunicationsTopicMagazineTypeFeature How Police Exploited the Capitol Riot's Digital Records 06 Jan 2023 11 min read Illustration of the silhouette of a person with upraised arm holding a cellphone in front of the U.S. Capitol building. 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