The Kynix Blog

In ancient Asia and Europe, "cutting the flesh to cure a boil" has a history of nearly 2500 years, but considering the level of medical treatment and anesthesia at that time, this seems to be more of torture. For irreparable damage to skin tissue, skin grafting is almost the only option considering the body's repulsive reaction. Doctors mainly rely on the removal of the patient's own skin or the skin of others for transplantation repair. Not to mention the unbearable pain, it will also leave new wounds on the patient's skin.In addition, the source of skin grafts for patients with large-area skin injuries is also a problem. The skin after transplantation is very fragile, with sequelae such as weakened sense of touch and decreased immunity.With the efforts of scientists from all over the world, the super-simulation electronic skin model is maturing. If it is put into human trials, this will be a good news for patients. This is a video introducing electronic skin Based on the development of electronic skin in recent years and the shortcomings of current wearable devices, this blog will introduce you to the structure of electronic skin and its future applications in the field of mobile health. Catalog  Ⅰ Introduction to electronic skinⅡ Development of electronic skinⅢ Electronic skin system architecture3.1 Flexible substrate3.2 Flexible battery3.3 Wireless communicationsⅣ Electronic Artificial Skin for   ApplicationⅤ ConclusionFAQ   Ⅰ Introduction to electronic skin Electronic skin, a system that allows robots to produce tactile sensations. It is not only simple in structure, but also can be processed into various shapes, and can even be attached to the surface of the device like clothes, allowing the robot to perceive information such as the location, orientation, and hardness of the object.Basic functions of electronic skin:From obtaining physical stimulation to distributed sensor array;Preprocess the sensor signal;The signal is transmitted wirelessly to higher-level systems (such as smart phones)The electronic skin is equipped with highly sensitive conductive nanomaterials, which can accurately cause slight tremors of the electrical changes of the muscle group. At the same time, the electronic skin is extensible (for example, it supports joint movement), and can even form integrated chemical sensors and biosensors.Therefore, electronic skin enables us to perceive different shapes and textures, temperature changes and different contact pressure levels. And, this is an integrated, scalable sensor network that can provide tactile and thermal signals to the brain, allowing us to operate safely and effectively in the surrounding environment. Human skin with distinctive features is a physical barrier to our interaction with the surrounding environment. Inspired by these features of human skin, researchers are working hard to create a flexible, scalable, and highly sensitive electronic device. Therefore, the development of electronic skin has become a research hotspot, especially in the fields of intelligent robots and electronic medicine.Ⅱ Development of electronic skinThe development of electronic skin technology could be divided into two stages:1）From 1970s to 1990s, the concept of e-skin appeared for the first time and got a preliminary development.2）Since 2000s, more researchers have been involved and have made a significant progress in recent years.In 1974, Clippinger demonstrated the feedback of a discrete sensor for a prosthetic hand. In 1985, General Electric first built a robotic arm sensitive skin which enabled to interact with the environment, placed on a flexible, curved sheet using discrete infrared sensors. In the 1990s, more and more teams began to create large-area, ultra-thin, multi-sensor flexible sheets. Jiang et al. first proposed a bent sensor sheet which obtained by etching thin silicon wafers and then integrating them on flexible polyimide film. In 2000, the organic transistor electronic nose was developed. Later, more achievements were made, such as scalable inverters, flexible active matrix technology, high resolution optical sensors, microstructured pressure sensors and so on. In 2003, the research team at the University of Tokyo in Japan made thin films by using low molecular organic compounds and realized the pressure of electronic skin through the pressure sensors on its surface. In 2010, the University of California, Berkeley, developed a technology to attach nanowire transistors to a sticky substrate, the resulting e-skin therefor could apperceive less than 50 grams of fine pressure and has been subjected to bending 2000 times. A woman scientist of Stanford University Bao Zhenan and her team have developed a highly sensitive flexible plastic film material that mimics human skin and senses subtle pressure. At the same time, the team developed the world's newest stretch solar cells, allowing electronic skin to self-generate electricity. In 2011, a researcher named John A.Rogers introduced an electronic patch for monitoring patient vital signs which described as "electronic skin." This device embedded the sensors in a film and placed the film on a flexible polyester substrate, like a kind of tattoo on the body. Physiological indexes of human health In 2014, electronic skin, developed by a researcher from the Chinese Academy of Sciences, was pasted on the human skin by static electricity, enabling real-time monitoring of physiological indexes of human health such as pulse, heartbeat, body temperature, muscle group vibration and so on, to promptly make a respond with feedback on changes of human health data. Ⅲ Electronic skin system architectureCompared with the current intelligent wearable devices, electronic skin has the characteristics of high sensitivity, ultra-thin, bendability and comfort in guardianship and monitoring the important physiological information of human body. E-skin system is a new type of flexible and extensible sensing system. By making sensors and circuits built on flexible substrates, e-skin systems can obtain unique ductility and more sensible to the various physical, chemical and biological signals. In the field of health care, the emergence of electronic skin will change the imprecise measurement of wearable devices, reduce the number of heavy monitoring equipment in the ward, and enable medical staff obtain the patient's physiological parameters in real time.Figure 1. Architecture of electronic skin systemFigure 2. E-skin structureFigure 3. Relationship between modules of e-skin system in medical applicationsThis system provides flexible circuits on flexible substrate, including microprocessors, Bluetooth and a variety of sensors (temperature, humidity and pressure sensors, blood oxygen, skin impedance and ECG sensors, etc.), which are connected to smart phones via Bluetooth. With the help of big data technology and cloud computing analyzes the data,  giving the diagnosis and treatment in time.Figure 4. Application scene of electronic skin system in mobile healthcareFigure 5. Electronic skin attached to temple to track brain wavesJohn Rogers, a professor of materials at the University of Illinois, Urbana-Champaign, has developed an e-skin called Biostamp, which can track brain waves in real time by sticking a flexible small sensor to a user's temple, able to show your deepest thoughts and feelings and translate them into information.Figure 6. Industrial designers of wearable health-monitoring electronicsIn the above structures, different applications have different requirements for sensors, and microcontrollers are becoming more and more lightweight in the field of electronic skin. So the following three parts of flexible substrate, power management and wireless communication technology will be described in detail.3.1 Flexible substrateOne of the most basic properties of electronic skin is that it has bending property, which can better attach to a large area of surface of human body One of the most basic properties of electronic skin is that it has bending property, which can better attach to a large area of human body surface. To achieve this property, the choice of materials is crucial. Advances in technology have enabled e-skin to be manufactured largely through the development of new materials and new processing methods. At present, polydimethylsiloxane (PDMS) and nanomaterials are commonly used as substrate materials:3.1.1 PDMSPDMS film is one of the most popular flexible substrates, including the advantages of good chemical inertia, being stable in a wide range of temperature, high transparency, variable mechanical properties and good adhesion to silicon wafer. At present, many research groups use PDMS as a flexible substrate. Sigurd Wagner and others used PDMS as a flexible substrate and found that wavy wires built into the film greatly enhanced its extensibility, such as obtaining skin tactile sensor arrays by printing silk screen on the PDMS film. The hypersensitive electronic skin equipment was fabricated by combining homogeneous microcosmic PDMS films with carbon nanocrystalline films.3.1.2 Nanophase materialsNanomaterials are a new type of materials developed in recent years. The current technological trends in the field of new materials are as follows:1. Carbon nanotubes: Compared with the zero-dimensional nanostructures such as carbon black, the one-dimensional carbon nanotubes have higher draw ratio and better electrical conductivity, which are used as conductive filler and then filled with the polymer composite can show lower resistivity and higher electrical conductivity.Figure 7. Schematic of carbon nanotube2. Graphene: Graphene is a hexagonal honeycomb structure consisting of a single layer of carbon atoms. It is the thinnest and strongest superconducting material ever known, which has a superior thermal, mechanical and electrical properties to carbon nanotubes, and with the tunneling effect it obtains a tactile sensor with high sensitivity, having a great application prospect in the field of conductive composite materials. Carbon nanotubes and graphene can be used not only as flexible substrates, but also as various good materials for high sensitivity sensors and flexible batteries. There are teams have so far made achievements in these areas and we are believing that nanomaterials will dominate in the near future.Figure 8. Graphene's atoms arranged in honeycomb pattern3.2 Flexible batteryLightness and softness are two of the most basic characteristics of e-skin. Traditional batteries can no longer meet the requirements of e-skin, but the  foldable and bendable flexible cell has become an indispensable part of e-skin equipment.Table 1. Comparison of current flexible batteryResearch instituteCellPerformanceProLogium Corporation, TaiwanUltra-Thin、Flexible FPC Lithium-Ceramic BatteryCuttable like paper, but cause no fire or explosion under bending, hammering, piercing, and 700-1300 ℃ high temperature gun fireImprint Energy, California, USAFlexible ultrathin zinc polymer battery3D printers in general use can be mass-produced at lower costRice University, USASuper-thin, High -performance flexible lithium free BatteryAfter 10,000 times of charge and discharge, or a thousand bends, it still maintains a capacity of 76%New Jersey Institute of TechnologyFlexible carbon nanotube cellIt can be made into various shapes and sizes, even DIY at homeSamsung Corp.Flexible bendable cellOrganic thin-film solar cellsFraunhofer Institute for Applied Polymer Research, GermanyOrganic thin film solar cellOrganic thin-film solar cellsNorthwestern University,USAFlexible stretchable lithium batteryStretchable, bendable, foldable and rechargeable wirelessly In addition to the flexible batteries mentioned above, a wireless charging technology developed in recent years also provides an alternative to the realization of electronic skin, including kinetic energy (motion, vibration, rotation) thermal energy, piezoelectricity and even radio waves (which can be viewed as wireless energy recovery) can be converted into usable electricity to provide a long-time even permanent energy supply. While it is still hard to really apply it to reality at the moment, it will be a new and innovative breakthrough in the future.3.3 Wireless communicationsIn recent years, in order to meet the requirement of intelligent equipment short-range communication, the automation short-range wireless technology emerges as the times require. At present, among all kinds of short-range wireless communication technologies, several mainstream of it such as Wi-Fi, ZigBeec, NFC, BLEID, UWB and so on become the main means for intelligent devices to communicate with each other at present. In e-skin system, wireless communication is still an indispensable part, and even has a higher requirements in communication performance, application environment and low power consumption.Table 2 Comparison of Wireless Communication TechnologyWireless technologyTransmission range / mMaximum transmission rate /MbpsTransmitting power / MWWi-Fi10-3054<50Zigbee10-100250kbps30NFC<20cm424kbps Bluetooth(BLE)10-1001~10RFID(UHF)<30~100kbps UWB3-10480 Wi-Fi is widely used in smart phones, and its fast transmission speed is an obvious advantage. Bluetooth is a wireless technology with low power consumption, ideal transmission distance and low cost. With the popularity of smart phones and the integration of Bluetooth modules, along with its gradually enhanced storage and computing capabilities, continuous real-time monitoring of the human body becomes possible. At the same time, the smart phone is used in the wearable health monitoring system as the information gateway to transmit the received physiological information, therefore the real-time monitoring of patients' health status has realized together with the emergence of big data technologies and cloud Computing. Bluetooth technology is the first choice for human-body monitoring system to transmit physiological signals in electronic skin. Ⅳ Electronic Artificial Skin for Application Figure 9. Electronic skin to monitor heart rateBiological tissue tends to be curved and soft, and most of the current wearable health monitoring devices are hard, rigid and difficult to achieve a large area of surface attachment. From an application point of view, this is not conducive to obtaining physiological signals from the human body. However because the e-skin has a flexible substrate which can be attached to a large area of tissue surface, and its sensors with high sensitivity can obtain the physiological signals of human body more accurately. Due to the unique properties of e-skin and the development of miniaturization technology, e-skin has great application potential in the fields of health monitoring, prosthesis, robot and so on.Figure 10. Intrinsically stretchable transistorIn the field of health care, electronic skin will have more applications, as shown in figure 11: Blood glucose detection;Speech recognition;Infant temperature monitoring;Intelligent Drug Administration, etc.Figure 11. Applications of electronic skin in health careIt is important for diabetics to be able to know their blood sugar changes all the time. Continuous blood glucose monitoring system can measure the patients’ blood glucose concentration with sensors containing specific enzymes.Speech recognition system(ASR) is an e-skin device attached to the throat of human body. It can monitor the weak pressure changes produced by muscle movement and transform them into speech, helping the deaf and mute to realize their dream of "speaking".Infant monitoring system can monitor the temperature, heart rate and other physical status of the baby in real time, and meanwhile feed back to the intelligent terminal in time.The intelligent drug delivery system can inject drugs regularly and quantitatively by placing them into the e-skin and monitoring the recovery of wounds by intelligent terminal control.With the combination of electronic skin and intelligent equipment, it is only necessary to transmit and analyze the signals obtained by e-skin to the intelligent equipment through wireless communication technology, then it has been able to monitor and provide feedback on the health condition of the human body in real time and in long distance. Electronic skin, as a new type of wearable device, will in the future provide real-time detection of blood pressure, blood sugar, heart rate, body temperature and etc. It is the best choice for real-time diagnosis and evaluation of human health. Ⅴ Conclusion The application prospect of e-skin is very extensive, not only in the field of health care, but also in the fields of consumer electronics, military affairs and even the more sci-fi robot "imitation of human skin", which will bring about revolutionary breakthroughs.With the endless emergence of wearable electronic devices, high sensitivity and miniaturization will become the mainstream trend. The emergence of electronic skin will undoubtedly bring about major technological breakthroughs and innovation opportunities for flexible wearable electronic devices.  FAQ 1. What is electronic skin used for?Flexible circuits inspired by human skin offer options for health monitoring, prosthetics and pressure-sensing robots. 2. What are the advantages of an e-skin?It helps the body to adjust after the transplant. It can make robots more sensitive. The use of tiny electronic wires allows the skin to generate impulses, similar to that of the body's own nervous system. It could lead to advancements in medical equipment. 3. What electronic skin is flexible?Electronic skin refers to flexible, stretchable and self-healing electronics that are able to mimic functionalities of human or animal skin. ... Advances in electronic skin research focuses on designing materials that are stretchy, robust, and flexible. 4. What is the main difference between flexible skin like sensors and the human skin?Like human skin, AISkin also is quite durable; however, while human skin can only stretch about 50 percent, the sensor-based skin can stretch up to 400 per cent of its length without breaking, making the material useful in wearable technology applications. 5. Who invented electronic skin?Researchers from the National University of Singapore have developed an 'electronic skin', capable of recreating a sense of touch thanks to more than 100 small sensors. They hope the technology can be applied to prosthetic limbs, allowing users to feel texture, temperature and pain. 6. Where has electronic skin been developed?National University of Singapore. A team from the National University of Singapore created the skin device, which measures 1 square centimeter. The system contains 100 small sensors that attempt to recreate things like texture, temperature and even pain. The researchers call the device Asynchronous Coded Electronic Skin, or ACES. 7. What can the skin sense?Receptors that let the body sense touch are located in the top layers of the skin - the dermis and epidermis. The skin contains different types of receptors. Together, they allow a person to feel sensations like pressure, pain, and temperature. ... They may sense pain, temperature, pressure, friction, or stretch. 8. What is a skin sensor?Electronic skin sensors, also known as the wearable thin film sensors, can be directly placed on the human body to measure body parameters such as body temperature, heartbeat, sweat composition etc. ... Electronic skin sensors have applications in many areas such as healthcare, sports, robotics and prosthetics, etc. 9. How do you replicate human skin?It was found that the most common materials used to simulate skin are liquid suspensions, gelatinous substances, elastomers, epoxy resins, metals and textiles. Nano- and micro-fillers can be incorporated in the skin models to tune their physical properties. 10. How is electronic skin made?Research into conductive electronic skin has taken two routes: conductive self-healing polymers or embedding conductive inorganic materials in non-conductive polymer networks. ... embedded silver nanoparticles (AgNPs) into a polymer matrix, making the e-skin conductive. 

CatalogIntroductionⅠ Function of the PS Vita memory cardⅡ PS Vita Memory Card Capacity and PriceⅢ Top 4 Reasons why Vita Memory Cards are So Expensive3.1 Performance Level3.2 Security3.3 Different Sizes3.4 GameplayⅣProprietary PS Vita Memory Cards4.1 Money and Cost of PS Vita Memory Card4.2 Card Size of PS Vita Memory Card4.3 Limitations of PS Vita Memory Card4.4 Transfer Speeds of PS Vita Memory Card4.5 Security of PS Vita Memory Card4.6 Wrap-up of PS Vita Memory CardⅤ Frequently Asked Questions about PS Vita Memory CardIntroductionDownloaded games from the Sony PlayStation Store require a PS Vita Memory Card to be saved. It's also necessary to recover game and add-on data. Photos, music, and other sorts of information are included. PS Vita is a memory card for use with the PS Vita or PS TV; Memory Stick media, such as the Memory Stick Micro, will not work with the PS Vita on your PSP device.Ⅰ Function of the PS Vita Memory CardDownloaded games from the Sony PlayStation Store require a PS Vita Memory Card to be saved. It's also necessary to recover game and add-on data. Photos, music, and other sorts of information are included. PS Vita is a memory card for use with the PS Vita or PS TV; Memory Stick media, such as the Memory Stick Micro, will not work with the PS Vita on your PSP device.Ⅱ PS Vita Memory Card Capacity and PriceSony offers five memory card sizes for the PS Vita: 4GB, 8GB, 16GB, 32GB, and 64GB. So, which size should you go with? This is dependent on your requirements as well as the cost.If your primary interest is in purchasing retail games, all you need is room for DLC and patches, thus a smaller card will suffice. It's fine to use an 8GB card. However, if you have PlayStation Plus and plan to buy and download games, a 32GB or 64GB card is advised.In terms of cost, a dedicated PS Vita memory card costs around three times as much as a microSD card of the same capacity, and the speed is only Class4. In a nutshell, the cost performance is exceptional. The PS Vita memory card is available on Amazon for the following price:4GB: $14.268GB: $14.3516GB: $42.9932GB: $71.9964GB: $132.99PS Vita memory cards come in five variants:4 GB (€ 12 to € 30 -> €3 to 7,5 per GB)8 GB (€ 26 to € 46 -> €3,25 to € 5,75 per GB)16 GB (€ 35 to € 55 -> €2,1875 to € 3,4375 per GB)32 GB (€ 65,- -> € 2,03125 per GB)64 GB (9580 yen, ~$94 -> $1,46875 per GB)Ⅲ Top 4 Reasons why Vita Memory Cards are So ExpensiveIf you're a gamer, you'll need a PS Vita memory card. To utilize the PS Vita, you'll need a memory card. Although some game cartridges have their memory, the Vita does not have any internal memory, which is equally puzzling. These cards, on the other hand, are required for data storage, game storage, and access to the downloaded material. It can be used with either the PS Vita or the PS TV.PS Vita memory cards are expensive because PS Vitas are no longer manufactured in the United States, therefore memory card vendors raise the price to make a profit on something they know a Vita user will require. They know Vita only uses one sort of card, and there is no competition.They maintain the price high since Vita uses just one type of card and has no rivals or competitors. The PlayStation Vita is a cutting-edge digital gaming console with outstanding hardware specifications, a stunning screen, and exceptional input capability.Only their proprietary memory cards are a drawback, as everyone seems to get along just fine using Formal SD Cards and their micro-equivalents.These cards are necessary for security reasons.Because these cards are proprietary, we must utilize them.This prevents users from installing pirated software.3.1 Performance LevelThese cards are used by Sony to maintain a high level of performance.It's safe to assume that the second rationale appears to be correct.We need a strong performance card for gaming so that we can play without lag.There are other reasons, according to users, why Vita cards are proprietary.The first is financial.If Sony is the only firm that makes these cards, it stands to reason that Sony is the only company that benefits from them.As a result, Vita cards are substantially more expensive than other Formal SD cards.3.2 SecurityPiracy is the next cause.You can limit how people use it by limiting the ps memory card options and hardware.These cards have security built in, and if you try to bypass it by downloading unlicensed software, your activity will be instantly refused.Performance is the third and last reason.Storage operates at a distinct pace.It has a direct impact on performance.The Vita card is virus-proof and will prevent any virus from entering it.As a result, they perform better than other formal SD Cards. 3.3 Different SizesBecause ps vita memory cards come in a variety of sizes, they display varying degrees of performance.The more the card's capacity, the better the performance.Of course, having the 16GB card has speed advantages, but getting the 32GB card has less fluctuation in write speed.What isn't clear is if the Content Manager is to blame for the slow write speeds, and whether or not encrypting/decrypting content plays a role.This could explain why game content and other data take so long to sync, but why would Content Manager encrypt a basic video file? It's incomprehensible.3.4 GameplayBecause Vita cards come in a variety of sizes, they display varying degrees of performance.The more the card's capacity, the better the performance.Of course, having the 16GB card has speed advantages, but getting the 32GB card has less fluctuation in write speed.What isn't clear is if the Content Manager is to blame for the slow write speeds, and whether or not encrypting/decrypting content plays a role.This could explain why game content and other data take so long to sync, but why would Content Manager encrypt a basic video file? It's incomprehensible.A 16GB Vita card costs roughly $49.99 at the time of writing, but a Class 10 MicroSD from a respectable brand with the same storage costs as little as $12.99 on Amazon.There is a significant price difference.Only if Vita Cards supply us with high-level performance is it a good investment.Ⅳ Proprietary PS Vita Memory Cards4.1 Money and Cost of PS Vita Memory CardThis is most likely the primary reason for Sony's fondness for PS Vita memory cards. The ones they create are the only ones available. And, as is the case with most business principles, fewer options mean greater prices. If you have a Vita, you will need to purchase a memory card because the gameplay is almost impossible without one (even with retail cartridges). With this in mind, Sony set card costs astronomically high, at least three times that of a SanDisk card. And, for the most part, the card is identical to a SanDisk, except some inconvenient encryption, which I will discuss later.Even the PS Vita 2000, which has 1GB of internal memory, requires the purchase of a memory card. 1 GB can only carry one or two half-decent games. So you fill it full and tell yourself, "I'll just go get a 4GB card so I can grab a couple more." Then you go out and get the 4GB card. You notice you've lost your internal memory of 1GB. When you insert a card into the PS Vita 2000, you lose your internal memory. It's just sitting there, unused. And gamers like us start to tremble a little as the fury builds inside of us.4.2 Card Size of PS Vita Memory CardWe also have a problem with the size of the cards. Sony looks to have learned from its mistakes in the past. It was their first attempt at a proprietary card with the PSP. They designed a card that was much larger than the others. Some people conducted some rocket science and determined that all you had to do was make an adaptor and put two normal cheapo cards into it. They made a card that is even smaller than the others this time, eliminating the need for an adaptor.The size of the cards is also an issue for us. Sony appears to have learned from its previous missteps. With the PSP, it was their first effort at a proprietary card. They made a card that was significantly larger than the rest. Some individuals did some rocket science and discovered that all you needed to do was construct an adaptor and insert two standard cheapo cards. This time, they created a card that is even smaller than the others, obviating the need for an adaptor.First, deceive us with your exorbitant prices, then remove a significant chunk of our space, and finally, leave us with no space to store our games. Oh, no problem; all you have to do is acquire another card and swap them out for a few seconds. No.4.3 Limitations of PS Vita Memory CardOn memory cards, you can't swap PSN accounts. You can, I suppose, but it's a huge pain. To swap accounts on your card, you must first back it up, format it, then reset your PS Vita system before inserting the new one. This is something you must do for each one of them. Single. Swap. Backing up isn't easy either (I'll explain why under the next heading). So, even if you have various game libraries on different memory cards, swapping them is a lot of fun:).The limit of one PSN account per card is something that goes hand in hand with the swapping disaster. It's the same process as swapping cards to have more. Why is there only one account? On the PS3 and PS4, you can have as many as you want. It's very paranoia-inducing.4.4 Transfer Speeds of PS Vita Memory CardFor one thing, I admire your patience if you are one of those constant swappers. Another thing you've probably noticed is the absurd backup and restore times. The PS Vita memory card read and write speeds are excruciatingly slow. It will take hours to backup and even longer restore.Transfer speeds have an impact not only on data transfer but also on gameplay. When playing digital games, the system must read data from the card. You may encounter lags, bugs, glitches, and even crashes as a result of this. This is not something you want to deal with, given that people play games for fun and entertainment.4.5 Security of PS Vita Memory CardThis is the big hit for the hacking and modding communities right now. It has an impact on the hacking scene due to the obvious fact that encryption is difficult to crack. Some significant progress has been made in cracking the PSP wide open via the unencrypted Memory Stick Duo, but access via the card is useless for the Vita.Modders, or more accurately, those who could have created a low-cost alternative to save our money, are unable to perform their duties. Only cards with the special encryption will be accepted by the PS Vita system. It's a no-go once more.4.6 Wrap-up of PS Vita Memory CardPS Vita memory cards are severely flawed for their users and could benefit from a significant upgrade. Sony doesn't care because they're making money, so we'll just have to suck it and sit in the permanent indents on our couches from gaming marathons. The consumer will be ruled by a business.That's all I've got for now, The Jay Doctor. Now that you've read my views and outrage-inducing points, share your thoughts in the comments or on Twitter, where you can drop me a line and even follow me if you want, using the handy links below. You can also follow Wololo.Ⅴ Frequently Asked Questions about PS Vita Memory Card1. How do you deactivate a PS Vita?It is best to turn off your PS Vita if you are not using it. Go to Settings > Power Save Settings > Set Time and Turn Off Device to accomplish this.2. Can PS Vita use micro SD cards?Micro SD cards can be used with the PS Vita.3. How do I start my PS Vita in safe mode?All you have to do to start your PS Vita in safe mode is to press and hold the power button for 10 seconds.4. How much GB does PS Vita have?Internal storage on the PS Vita is 1 GB.5. Does PS Vita store still work?No, the PS Vita store is no longer operational. Internal storage on the PS Vita is 1 GB.

IntroductionPrinted Circuit Board(PCB) is a board of most modern electronic devices that has lines and pads that connect various points together. Even if it is a small board, its manufacturing process is very cumbersome and exquisite. Here will introduce the PCB manufacturing process steps by steps with pictures and video.How is PCB made?The following are the detailed PCB producing processes:IntroductionStep 1. PCB CAD FileStep 2. Plate ProductionStep 3. PCB Inner LayersStep 4. Board Punching and CheckingStep 5. LaminationStep 6. DrillStep 7. Copper Chemical Precipitation on the HolesStep 8. PCB Outer LayersStep 9. Computer Control and Copper ElectroplatingStep 1. PCB CAD FileThe first step in PCB production is to organize and check the PCB layout. The PCB manufacturers get the CAD files from the PCB design company, and they will convert them into a unified format-Extended Gerber RS-274X or Gerber X2, because each CAD software has its own unique file format. Then the electronic engineers will check whether the PCB layout conforms to the manufacturing process, and whether there are any defects and other issues.Figure 1. PCB CAD FileWhen making a PCB at home, the PCB layout can be printed on paper with a laser printer, and then transferred to the copper clad laminate. During the printing process, because the printer is prone to lack of ink and breakpoints, it is necessary to manually fill up the ink with an oil-based pen. Figure 2. PCB Laser PrintingHowever, the factory generally uses photocopying to print the PCB layout on the film. If it is a multi-layer PCB, the layout film photocopied on each layer will be arranged in order.Figure 3. PCB Film Arranged in OrderThen the film will be punched with alignment holes. Alignment holes are very important, which is essential to align the materials of each layer of the PCB.Step 2. Plate ProductionClean the copper plate. If there is dust, it may cause the final circuit to be short-circuited or broken.Figure 4. Clean the Copper PlateThe figure below is an example of an 8-layer PCB, which is actually made up of 3 copper clad laminates plus 2 copper films, and then glued them together with prepregs. The production sequence is to start with the middle board (4th- and 5th-layer of circuits), continuously stack together, and then fix. The production of 4-layer PCB is similar, including one core board and two copper films.Figure 5. 8-layer PCB Plate DisplayStep 3. PCB Inner LayersFirst, make the two-layer circuit of the middle core board. After the copper clad laminate is cleaned, it will be covered with a photosensitive film on the surface. This film will solidify when exposed to light, forming a protective film on the copper foil.Figure 6. PCB CoreInsert the two-layer PCB layout film and the double-layer copper clad laminate into the upper PCB layout film to ensure that the upper and lower PCB layout films are stacked accurately.Figure 7. PCB Layout Film PlacingThe machine irradiates the photosensitive film on the copper foil with a UV lamp. The transparent film is cured under the light, and there is still no cured photosensitive film. The copper foil covered under the cured film is the required PCB layout, which is equivalent to the function of the laser printer ink of the manual PCB. In addition, the copper foil covered by the black film will be corroded away, and the cured transparent film will be preserved.Figure 8. Cured Photosensitive FilmClean the uncured photosensitive film with lye, and the required copper foil circuit will be covered by the cured film.Figure 9. Clean Uncured Photosensitive FilmThen use a strong base, such as NaOH, to etch away the unnecessary copper foil.Figure 10. Copper Foil EtchingTear off the cured photosensitive film to expose the copper foil of the required PCB layout.Figure 11. Tear Off the Cured Photosensitive FilmStep 4. Board Punching and CheckingThe core board has been successfully produced. Then punch alignment holes on it to facilitate with other materials.Figure 12. Punch Alignment Holes on PCBOnce the core board is pressed together with other layers, it cannot be modified. So PCB checking is very important. The machine will automatically compare with the PCB layout drawing to find out the error.Figure 13. PCB Layout Drawing ComparisonThe first two layers of PCB boards have been made.Step 5. LaminationA new raw material is introduced here called Prepreg, which is the adhesive among the core boards(PCB layers>4), as well as the core board and the outer copper foil, and it also plays a role in insulation.Figure 14. PCB Prepreg and CopperThe lower copper foil and the two layers of prepreg have been fixed in advance through the alignment hole and the lower iron plate, and then the finished core board is also placed in the alignment hole, and finally the two layers of prepreg, a layer of copper foil and a layer of pressure-bearing aluminum plate covers the core plate.Figure 15. Fixed PCB Prepreg and CopperIn order to improve work efficiency, this factory will stack three different PCB boards together before fixing them. The upper iron plate is magnetically attracted to facilitate alignment with the lower iron plate. After the two layers of iron plates are successfully aligned by inserting the alignment pins, the machine compresses the space between the iron plates as much as possible, and then fixes them with nails.Figure 16. Fixed PCB LayersThe PCB boards clamped by the iron plates are placed on the holder, and then sent to the vacuum heat press for laminating. The high temperature can melt the epoxy resin in the prepreg and fix the core boards and copper foils together under pressure.Figure 17. PCB Layers LaminationAfter the lamination, remove the upper iron plate that presses the PCB. Then remove the pressure-bearing aluminum plate. The aluminum plate also plays the role of isolating different PCBs and ensuring the smoothness of the outer copper foil of the PCB. Finally the PCB taken out at this time will be covered by a layer of smooth copper foil.Figure 18. Remove the Upper Iron Plate and Aluminum PlateStep 6. DrillSo how to connect 4 layers of copper foils that are not in contact with each other in the PCB? First, make the through-hole through the PCB, and then metalize the hole wall to conduct electricity.Figure 19. PCB DrillPut a layer of aluminum plate on the punching machine, and then put the PCB on it. Since drilling is a relatively slow process, in order to improve efficiency, according to the number of layers of the PCB, 1 to 3 identical boards are stacked for drilling together. Finally, cover the uppermost PCB with a layer of aluminum plate. The upper and lower of aluminum plates are used to prevent the copper foil on the PCB from tearing when drilling.Figure 20. PCB DrillNext, you only need to select the correct drilling program on the computer, and the rest is done automatically by the drilling machine. The drill bit is driven by air pressure, and the maximum rotation speed can reach 150,000 revolutions per minute. Because such a high rotation speed is sufficient to ensure the smoothness of the hole wall.Figure 21. Drill ProgramThe replacement of the drill bit is also automatically completed by the machine according to the program. The smallest drill bit can reach a diameter of 100 microns, while the diameter of a human hair is 150 microns.Figure 22. Drill ReplaceIn the previous process, the molten epoxy was squeezed out of the PCB, so it needed to be cut off. Here the profiling milling machine cuts its periphery according to the correct XY coordinates of the PCB.Figure 23. Cuts PCB PeripheryStep 7. Copper Chemical Precipitation on the HolesSince almost all PCB designs use perforations to connect different layers of lines, a good connection requires a 25-micron copper film on the hole wall. The thickness of the copper film needs to be realized by electroplating, but the hole wall is composed of non-conductive epoxy resin and glass fiber board. So the first step is to deposit a layer of conductive material on the hole wall, and form a 1 micron copper film on the entire PCB surface by chemical deposition. The entire process such as chemical treatment and cleaning is controlled by the machine.Step 8. PCB Outer LayersNext, the PCB outer layer is transferred to the copper foil. The process is similar to the transfer principle of the previous PCB inner core board. The PCB layout is transferred to the copper foil by photocopying film and photosensitive film. The only difference is positive films will be used as boards.The transfer of the internal PCB layout described above uses the subtractive method, and the negative film is used as the board. The PCB is covered by the cured photosensitive film as a circuit, and the uncured film is cleaned. After the exposed copper foil is etched, the PCB layout circuit is protected by the cured film. The transfer of the outer PCB layout adopts the normal method, and the positive film is used as the board. The non-circuit area is covered by the cured photosensitive film on the PCB. After cleaning the uncured film, electroplating is performed. Where there is a film, it cannot be electroplated, and where there is no film, copper is plated first and then tin is plated. After the film is removed, alkaline etching is performed, and finally the tin is removed. So the circuit pattern remains on the board because it is protected by tin.Put the cleaned PCB on both sides of the copper foil into the laminating machine, and the photosensitive mold will be pressed onto the copper foil.Figure 24. LaminatorFix the printed PCB layout film of the upper and lower layers through the holes, and put the PCB board in the middle. Then, the photosensitive film under the light-transmitting film is cured by the irradiation of the UV lamp, which is the circuit that needs to be reserved.Figure 25. PCB Expose to the UV LightAfter cleaning off the unnecessary and uncured photosensitive film, inspect the PCB board.Figure 26. PCB CheckingClamp the PCB with clips, and electroplate the copper. As mentioned earlier, in order to ensure that the holes have sufficient conductivity, the copper film plated on the hole walls must have a thickness of 25 microns, so the entire system will be automatically controlled by the computer to ensure its accuracy.Figure 27. PCB Copper PlatingStep 9. Computer Control and Copper ElectroplatingAfter the copper film is electroplated, the computer gives instructions to electroplate a thin layer of tin. Then, check to ensure that the thickness of the plated copper and tin is correct.Figure 28. Electroplated Copper and Tin InspectionNext, a complete automated assembly line completes the etching process. Then, clean the cured photosensitive film on the PCB.Figure 29. Clean Cured Photosensitive FilmThen use a strong alkali to clean the unnecessary copper foil covered by it.Figure 30. Clean the Unnecessary Copper FoilFinally, use the tin stripping solution to strip the tin plating on the PCB layout copper foil. After cleaning, the 4-layer PCB layout is complete. Frequently Asked Questions about PCB Manufacturing Process1. Which are the techniques of PCB manufacturing?There are several PCB manufacturing methods that a PCB can be submitted to before reaching the final product. These methods include preparing the board's surface, placing components, soldering, cleaning, and inspection and testing. 2. What is PCB design process?Step 1 – The DesignStep 2 – Printing the DesignStep 3 – Creating the SubstrateStep 4 – Printing the Inner LayersStep 5 – Ultraviolet LightStep 6 – Removing Unwanted CopperStep 7 – Inspection.Step 8 – Laminating the Layers 3. Which software is best for PCB design?Top 8 Best PCB Design Software of 2021PROTEL (Altium Designer)PADS (PowerPCB)ORCADAllegroEagle (Easily Applicable Graphical Layout Editor)KicadEasyEdaFritzing 4. What is a PCB layer?A PCB is defined as a number of copper layers in a well defined sequence. Copper layers of a PCB are usually just named layers or also called SIGNAL layer. However, to define the complete PCB, other layers are required. They are usually named by their functionality and position. 5. What are the components of a PCB?Some common PCB components include:Battery: provides the voltage to the circuit.Resistors: control the electric current as it passes through them. They’re colour coded to determine their value.LEDs: light emitting diode. Lights up when current flows through it, and will only allow current to flow in one direction.Transistor: amplifies charge.Capacitators: these are components which can harbour electrical charge.Inductor: stores charge and stops and change in current.Diode: allows current to pass in one direction only, blocking the other.Switches: can either allow current or block depending if they are closed or open.

  Catalog Ⅰ Introduction Ⅱ Resistor network  in Series vs in Parallels 2.1 Resistor in Series  Ⅲ Resistor Circuit in Series vs in Parallels 3.1 Resistor Circuit in Series 3.2 Resistor Circuit in Parallels Ⅳ Equation in Series vs Parallels 4.1 Series Resistor Equation 4.2 Parallel Resistor Equation Ⅴ Examples 5.1 Resistors in Series Example 5.2 Resistor in Parallels Ⅵ Applications Ⅶ Summary 7.1 Resistors in Series Summary 7.2 Resistors in Parallel Summary Ⅷ FAQ Ⅰ Introduction   Individual resistors can be commonly connected to three types of circuits such as series, parallel, or a combination of series and parallel connections to form more complex resistor networks, the equivalent resistance of which is the mathematical combination of the individual resistors connected together.   A resistor is not only a fundmental electronic component that can be applied to convert a voltage to a current or a current to a voltage but it can also be used to place a different weighting on the converted current and/or voltage by correctly adjusting its value, allowing it to be used in voltage reference circuits and applications.    A single equivalent resistor can take place of resistors in series or complicated resistor networks. REQ, or impedance, ZEQ, and regardless of the resistor network's combination or complexity, all resistors follow the same basic rules defined by Ohm's Law and Kirchhoff's Circuit Laws.   Resistors in Series | Electricity and Circuits | Don't Memorise   Ⅱ Resistor network  in Series vs in Parallels     2.1 Resistor in Series   When resistors are daisy-chained together in a single line, they are connected in "Series." Because there is no other way for the current flowing through the first resistor to go, it has to pass through the second, third, and so on. The current that flows through one resistor should flow through the others as well because it can only take one path, so resistors in series have a Common Current flowing through them.   The current flowing through a series of resistors will then be the same at all points in a series resistor network. As an example:       Figure1：Current flowing through a series     In the following example, resistors R1, R2, and R3 are connected in series between points A and B, with a common current, I, flowing through them.         2.2 Resistor in Parallels In contrast to the previous series resistor circuit, the circuit current in a parallel resistor network can take more than one path because there are multiple paths for the current. Parallel circuits are then classified as current dividers.   Because the supply current can flow through multiple paths, the current may not be the same through all of the parallel network's branches. The voltage drop across all resistors in a parallel resistive network, on the other hand, so it is. Then, parallel-connected resistors have a common voltage across them, as do all parallel-connected elements.       Figure2: Circuit current in a parallel      Ⅲ Resistor Circuit in Series vs in Parallels   3.1 Resistor Circuit in Series         Figure3: Resistor Circuit in series     Because the resistors are linked in series, the same current flows through each resistor in the chain, and the total resistance, RT, of the circuit must equal the sum of all the individual resistors added together. That is            Figure4: resistance     and by taking the individual values of the resistors in our simple example above, the total equivalent resistance, REQ is therefore given as:   REQ = R1 + R2 + R3 = 1kΩ + 2kΩ + 6kΩ = 9kΩ     3.2 Resistor Circuit in Parallels       Figure5: resistor circuit in parallel     The total resistance, RT, of the circuit in the previous series resistor network was equal to the sum of all the individual resistors added together. The equivalent circuit resistance RT is calculated differently for parallel resistors. Instead of the resistances themselves, the reciprocal (1/R) value of each is added together, with the inverse of the algebraic sum giving the equivalent resistance as shown. Instead of the resistances themselves, the reciprocal (1/R) value of each is added together, with the inverse of the algebraic sum giving the equivalent resistance as shown.     Ⅳ Equation in Series vs Parallels 4.1 Series Resistor Equation Because it is the algebraic sum of the individual resistances, the total or equivalent resistance, RT, has the same effect on the circuit as the original combination of resistors. If two equal and of the same value resistances or impedances are connected in series, the total or equivalent resistance, RT, is equal to twice the value of one resistor. That is equal to 2R for two equal resistors in series, 3R for three equal resistors in series, and so on.         Figure6：Series Resistor Equation     If two series resistors or impedances are unequal and of different values, the total or equivalent resistance, RT, is equal to the mathematical sum of the two resistances. R1 + R2 is the answer. The equivalent resistance of three or more unequal (or equal) resistors connected in series is: R1 + R2 + R3 +..., etc.       Figure7：Equivalent resistance     One important thing to remember about resistors in series networks is to double-check your math. The total resistance (RT) of any two or more resistors connected in series is always greater than the value of the chain's largest resistor. In our previous example, RT = 9k, whereas the largest resistor value is only 6k.     4.2 Parallel Resistor Equation         The algebraic sum of the inverses of the individual resistances is the inverse of the equivalent resistance of two or more resistors connected in parallel. If the two parallel resistances or impedances are equal and of the same value, the total or equivalent resistance, RT, is equal to half the value of one resistor. That is R/2 for two equal resistors in parallel, R/3 for three equal resistors in parallel, and so on.       Figure8: Resistances or impedances     Because the equivalent resistance is always less than the smallest resistor in the parallel network, as more parallel resistors are added, the total resistance, RT, will always decrease.     Ⅴ Examples   5.1 Resistors in Series Example Calculate the voltage drops across X and Ya) Without RL connected   b) With RL connected         Figure9: series example     As shown above, the output voltage Vout without the load resistor connected gives us the required output voltage of 6V, but when the load is connected, the output voltage drops to only 4V. (Resistors in Parallel).   Then we can see that a loaded voltage divider network's output voltage changes as a result of the loading effect because the output voltage Vout is determined by the R1 to R2 ratio. However, as the load resistance, RL, approaches infinity (), the loading effect diminishes and the voltage ratio of Vout/Vs is unaffected by the addition of the load on the output. Then, as the load impedance increases, the loading effect on the output decreases.   Attenuation is the effect of lowering a signal or voltage level, so when using a voltage divider network, it is essential to have cautiousness. This loading effect could be compensated for by using a potentiometer instead of fixed value resistors and adjusting the potentiometer accordingly. This method also compensates the potential divider for variations in resistor tolerances.     5.2 Resistor in Parallels   Find the total resistance, RT of the following resistors connected in a parallel network.       Figure10: Total resistance     The total resistance RT across the two terminals A and B is calculated as:       Figure11: Total resistance RT     This reciprocal calculation method can be used to calculate any number of individual resistances connected in a single parallel network. If, on the other hand, there are only two individual resistors connected in parallel, we can use a much simpler and faster formula to find the total or equivalent resistance value, RT, and thus help reduce the reciprocal maths a little.         Figure12: Single parallel network     Ⅵ Applications   Series We've seen how Resistors in Series can be applied to generate different voltages across themselves, and how this genre of resistor network can be used to create a voltage divider network. We can convert an analog quantity being sensed into a suitable electrical signal that can be measured by replacing one of the resistors in the voltage divider circuit above with a Sensor such as a thermistor, light-dependent resistor (LDR), or even a switch.     Parallel The five resistive networks shown above may appear to be different, but they are all arranged as Resistors in Parallel, and thus the same conditions and equations apply.   Ⅶ Summary   7.1 Resistors in Series Summary When two or more resistors are connected end-to-end in a single branch, Reputedly, they are connected in series. Resistors in series carry the same current, but the voltage drop across them is not the same as their resistance values result in different voltage drops across each resistor, as determined by Ohm's Law (V = I*R). Then there are series circuits, which are voltage dividers. Individual resistors in a series resistor network add together to give the series combination's equivalent resistance, (RT). A series circuit's resistors can be swapped without affecting the total resistance, current, or power to each resistor or the circuit.     7.2 Resistors in Parallel Summary   When two or more resistors are connected in such a way that their terminals are connected to the terminals of the other resistor or resistors, they are connected in parallel. The voltage across each resistor in a parallel combination is the same, but the currents flowing through them are not because of their resistance value and Ohms Law. Parallel circuits are then used as current dividers. Reciprocal addition is used to find the equivalent or total resistance, RT, of a parallel combination, and the total resistance value is always less than the smallest individual resistor in the combination. Within the same combination, parallel resistor networks can be swapped without changing the total resistance or total circuit current. Resistors connected in a parallel circuit will continue to operate even if one of them is open-circuited.   Ⅷ FAQ   1. How do you calculate resistors in series? In a series circuit you will need to calculate the total resistance of the circuit in order to figure out the amperage. This is done by adding up the individual values of each component in series. ... To calculate the total resistance we use the formula: RT = R1 + R2 + R3. 2 + 2 + 3 = 7 Ohms. R total is 7 Ohms.     2. Do you add up resistance in series? How do you know if a series resistor is parallel? The trick is to look at the nodes in the circuit. A node is a junction in the circuit. Two resistor are in parallel if the nodes at both ends of the resistors are the same. If only one node is the same, they are in series.   3. Which resistor gets the most current? which resistor has the most current passing through it? the 5-Ω resistor has the most current passing through it, since I = V/R.     4. What is resistor connected in parallel? Resistors are in parallel if their terminals are connected to the same two nodes. The equivalent overall resistance is smaller than the smallest parallel resistor. Written by Willy McAllister.     5. What happens to resistors in parallel? When resistors are connected in parallel, more current flows from the source than would flow for any of them individually, so the total resistance is lower. Each resistor in parallel has the same full voltage of the source applied to it, but divide the total current amongst them.     6. Why do resistors decrease resistance in parallel? Resistors in parallel   In a parallel circuit, the net resistance decreases as more components are added, because there are more paths for the current to pass through. The two resistors have the same potential difference across them. ... The total current in the circuit is the sum of the currents through each branch.            

Introduction Capacitors are now commonly used as decoupling capacitors, DC blocking capacitors, or as matching capacitors due to their characteristics of blocking DC while passing AC. But in practical applications, DC can charge the capacitor and pass through it. Is this contrary to its characteristics? Why can DC charge the capacitor? Here we will discuss this issue in details. Charging and Discharging of Capacitor -RC Circuit Catalog Introduction Ⅰ Capacitor Charging Principle Ⅱ Why Capacitor Charges in DC? Ⅲ Capacitor Transient and Steady-state Processes Ⅳ Capacitor Circuit Analysis and Calculations Ⅴ FAQ Ⅰ Capacitor Charging Principle A capacitor is a component that can store electrical energy. As one of the most commonly used electronic components, the simplest capacitor is composed of plates at both ends and an insulating dielectric (including air) in the middle. After being energized, the plates are charged to form a voltage (potential difference), but due to the insulating material in the middle, the entire capacitor is non-conductive. However, this situation is under the premise that the critical voltage (breakdown voltage) of the capacitor is not exceeded. In fact, any substance is relatively insulating. When the voltage across the substance increases to a certain level, the substance can conduct electricity. We call this voltage breakdown voltage.It is the same for the capacitor. After the capacitor is broken down, it is not an insulator. In an AC circuit, because the direction of the current changes with time as a certain function. The process of charging and discharging a capacitor takes time. At this time, a changing electric field is formed between the plates, and it is also a function of time. So current passes between capacitors in the form of an electric field.Capacitors are similar to batteries in that they also have two electrodes. Inside the capacitor, the two electrodes are connected to two metal plates separated by a dielectric. When the capacitor is connected to the power supply, under the action of the electric field force, the free electrons of the capacitor plate connected to the positive electrode of the power supply will move to the negative electrode. The positive electrode is positively charged due to the loss of negative electrons, and the negative electrode is negatively charged due to its negative electrons. In addition, the charges on the positive and negative plates are equal, with opposite signs.The directional movement of the charge forms a current. Due to the repulsion of the same charges, the current is the largest at first, and then gradually decreases. During the charge movement, the charge stored in the capacitor plate continues to increase, and the charge stops moving when the voltage between the two plates of the capacitor is equal to the power supply voltage. That is, the current I=0, the switch is closed, and the positive and negative plates of the capacitor are neutralized through the connection of the wires. When the switch is closed, the positive charge of the positive pole of the capacitor can be moved to the negative pole and neutralized. When the charge gradually decreases, the current decreases, and the voltage gradually decreases to zero.   Ⅱ Why Capacitor Charges in DC? Why is there a charging current that lasts for a period of time when using DC to charge a capacitor? At this time, the circuit is equivalent to an open circuit, there is no continuous current without a loop, and the capacitor charging has time, not instantaneously, so the instantaneous current is not the answer. Having a potential difference, how does a circuit without a closed loop produce a charging current that lasts for a period of time? Figure 1. Transition Process When Charging the Capacitor The voltage across the capacitor is not allowed to change suddenly. So when the power is turned on, the voltage across the capacitor is equal to zero, and then the voltage rises exponentially until it enters a steady state. The capacitor after entering the steady state is equivalent to an open circuit. In fact, the capacitor can block the constant direct current and disconnect when it fully charged in the circuit. According to the leakage resistance of the capacitor, the charge can be stored in the capacitor for a long period of time.When Usr is instantly added to the resistor-capacitor circuit, because the voltage across the capacitor is not allowed to change suddenly, the capacitor is equivalent to being short-circuited at this time. So at time 0, the current flowing through the capacitor and resistor R is .Then the capacitor began the charging process, and the current became smaller and smaller. After 5 times the RC time, the capacitor charging is basically over and the current is reduced to zero. Since then, it has entered a steady state. The RC(τ) here is called the time constant.We know that resistance is equal to the ratio of voltage to current, that is, R=U/I. We also know that the capacitance C is equal to the ratio of the electric quantity Q to the voltage U, and the electric quantity Q is equal to the product of the current I and the time t .It turns out that the product of resistance and capacitance is time. The unit of resistance is ohms and the unit of capacitance is farads, so the unit of time is seconds.In Figure 1, when the capacitor is charged, the voltage across it is .We find Uc when t=0, 1RC, 2RC, 3RC, 4RC, and 5RC, as follows: It can be seen that when time t=0, the voltage across the capacitor is equal to zero; when t=5RC, the voltage across the capacitor is almost equal to the input voltage.Let's look at the current flowing through the capacitor, its expression is as follows: When t=5RC, where .It can be seen that the current at this time is almost equal to zero. Therefore, the transient process and steady-state process of the capacitor must be clearly distinguished.   Ⅲ Capacitor Transient and Steady-state Processes 1) There are transient and steady-state processes in the capacitor charging circuit.2) At the beginning of capacitor charging, it must be considered that the voltage across the capacitor does not allow sudden changes, which is an important principle.3) The transient process generally ends after 5τ.4) For Figure 1, at the moment of the transient start, the capacitor voltage Uc is equal to zero, and the current Ic is equal to the maximum value. We know from Ohm's law that the equivalent resistance of the capacitor is equal to zero . Usually we say that the capacitance at this time is equal to the short circuit i. In the steady state at the end of the transient, the capacitor voltage Uc is equal to the input voltage Usr, and the capacitor current Ic=0. According to the Ohm's law that the equivalent resistance of the capacitor is equal to infinity . At this time, the capacitance is equivalent to an open circuit.5) If the input signal voltage is a short pulse, the capacitor can transmit the signal to the load; if the input signal is a constant voltage, the capacitor will only respond during a short transition, and then block the input signal; if the input signal is an AC signal, which is exactly in the middle of the above two situations.The higher the frequency of the AC signal, the easier it is to pass through the capacitor. We call this feature a high-pass filter function. Although the AC signal can pass through the capacitor, there will be a certain amount of clipping. This shows that the capacitor has the function of isolating DC in the steady state, and a high-pass characteristic. So we can further analyze, any circuit with capacitor and inductor, we must analyze the circuit according to the transient state and the steady state, in order to get the correct analysis result.   Ⅳ Capacitor Circuit Analysis and Calculations The analysis is available from the figure below: Figure 2. Output Voltage Usc If set Usr=10Vdc, the capacitance is equal to 10 microfarads, and the resistances R1 and R2 are both 1 kiloohm, then how to analyze the value of Usc?Step 1: Determine the time constant of the capacitor. Figure 3. Usr in Short-circuit Connection From the analysis of the above figure, it can be seen that the time constant is 20 milliseconds , and the time for 5 times the time constant is 0.1 seconds.Step 2: Let's calculate the specific value of Usc.When Usr in Figure is just established, the capacitor voltage drop is equal to zero, so there is .After 5τ, the capacitor is full of voltage, and its value is Uc=Usr, so Usc=0, .When charging starts, t=0, When the time has passed 0.1 second, we have , and the Usc at this time is almost equal to zero. Now, let's connect R1 and C in parallel, and see what happens: Figure 4. R1 and C are Connected in Parallel We see that if Usr in the figure is short-circuited, R1 and R2 are connected in parallel, so the time constant is At the beginning of Usr power on, C is equivalent to a short circuit, and Usr is directly loaded on both ends of the resistor R2, so at this time Usc=UseWhen the circuit enters a steady state, Usc is equivalent to the partial pressure of Usr by resistors R2 and R1, namely Based on this, we can derive the following equation: .In the above formula, the first term on the right side of the equal sign is the change in capacitor voltage, which reflects the transition process. The second term on the right side of the equal sign is the final steady-state voltage.Substitute the parameters, and calculate the time constant first: .In other words, when the time is 5τ, that is, 25 microseconds, the output voltage tends to stabilize. The final value is .It is still 5V, but the transition process is only 25 microseconds, which is much shorter than the previous 0.1 second.   Ⅴ FAQ 1. When a capacitor is charging in a DC circuit?At this point, the electric field between the plates cancels the effect of the electric field generated by the battery, and there is no further movement of charge. Thus, if a capacitor is placed in a DC circuit then, as soon as its plates have charged up, the capacitor effectively behaves like a break in the circuit.   2. What happens to the current in a DC circuit once a capacitor is charged?For a capacitor charge Q = capacitance C multiplied by voltage V. This quite simply means that a rate of change of voltage gives rise to a current. If the voltage is rising linearly with time, the capacitor will take a constant current and once the voltage stops changing the current is zero.   3. Does current flow in a DC circuit while a capacitor is charging?Yes. For DC circuits, when a capacitor is charged or discharged, current is flowing into and out of it. For AC circuits, a capacitor can act almost like a "resistor" but instead it is called reactance. But alas, current does flow through the capacitor.   4. Do capacitors charge with AC or DC?When DC current is applied to a circuit with only resistance and capacitance, the capacitor will charge to the level of the applied voltage. Since DC only flows in one direction, once the capacitor is fully charged there is no more current flow.   5. Can we use capacitor in DC?Capacitors can be used in many different applications and circuits such as blocking DC current while passing audio signals, pulses, or alternating current, or other time varying wave forms. ... At DC a capacitor has infinite impedance (open -circuit), at very high frequencies a capacitor has zero impedance (short-circuit).   6. Can a capacitor be charged by DC?When capacitor is connected to dc voltage source, capacitor starts the process of acquiring a charge. This will built up voltage across capacitor. Once capacitor has acquire enough charge, current starts flowing and soon capacitor voltage reaches at value approximately equal to dc source voltage.   7. Why does AC pass through capacitor but not DC?Capacitors have two parallel metallic plates placed close to each other and there is a gap between plates. A capacitor blocks DC but it allows AC. ... Therefore the electrons flowing in one direction (i.e. DC) cannot pass through the capacitor. But the electrons from AC source seem to flow through C.   8. What happens when capacitor is connected to DC?When capacitors are connected across a direct current DC supply voltage, their plates charge-up until the voltage value across the capacitor is equal to that of the externally applied voltage. ... Then the Capacitance in AC circuits varies with frequency as the capacitor is being constantly charged and discharged.   9. Why capacitor is used in DC circuit?Capacitors are useful to reduce the voltage pulsation. When the high voltage is applied to the parallel circuit, the capacitor is charged, and on the other hand, it is discharged with the low voltage. While electricity flowing out is alternating current, most of electronic circuits work with direct current.   10. Why do capacitors block DC current?We know that there is no frequency i.e. 0Hz frequency in DC supply. If we put frequency “f = 0″ in the inductive reactance (which is AC resistance in capacitive circuit) formula. If we put XC as infinity, the value of current would be zero. That is the exact reason why a capacitor block DC.   11. How is a capacitor charged in a DC circuit?When used in a direct current or DC circuit, a capacitor charges up to its supply voltage but blocks the flow of current through it because the dielectric of a capacitor is non-conductive and basically an insulator. ... At this point the capacitor is said to be “fully charged” with electrons.   12. Which capacitor is used in DC circuit?Decoupling capacitor is used, where we have to decouple the two electronics circuits. In other words, the noise generated by one circuit is grounded by decoupling capacitor and it does not affect the performance of other circuit.   13. Can you charge a capacitor with DC current?A DC voltage source is used to charge a Capacitor. When the DC voltage source is outputting more than the DC voltage source can charge, the Capacitor will charge up. Capacitors will charge up to 9 volts if they are connected to a 9-volt battery.   14. What happens if DC is applied to capacitor?When capacitors are connected across a direct current DC supply voltage, their plates charge-up until the voltage value across the capacitor is equal to that of the externally applied voltage. ... Then the Capacitance in AC circuits varies with frequency as the capacitor is being constantly charged and discharged.   15. Can we charge capacitor with DC current?When capacitor is connected to dc voltage source, capacitor starts the process of acquiring a charge. This will built up voltage across capacitor. Once capacitor has acquire enough charge, current starts flowing and soon capacitor voltage reaches at value approximately equal to dc source voltage.

What is a LED?Video related to LEDLED Colours and materialsHow do LEDs work?Types of LedsCalculating LEDs resistor valueHow to Test LED LightsThe warning of LEDs useLEDs FAQWhat is a LED?LED = Light Emitting Diode. An LED must be prevented against transferring too much current because its electrical behavior differs significantly from that of a light. Typically, this is done by connecting a resistor in series with the LED. Never attach an LED directly to a power source or battery.LEDs must be wired in the proper direction; the diagram may be labeled with the letters an or + for the anode and k or - for the cathode (yes, it really is k, not c, for cathode). In the case of spherical LEDs, the cathode is the short lead and there may be a slight flat on the body. Although the cathode is the larger electrode within the LED if you can see it, this is not a recognized method of identification.LEDs Video related to LEDVideo Description: This video is mainly talk about how to design LED circuits, how to calculate resistor size, how to protect LED, how long will a battery power a circuit, how to calculate resistor power rating, how to connect LED and much more. LED Colours and materialsThe semiconductor material, not the coloring of the "package," determines the color of an LED (the plastic body). All colors of LEDs are available in uncolored, diffused (milky), or clear (commonly referred to as "water clear") packaging. The colored packaging is also offered in diffused (the typical type) and clear forms. White and blue LEDs could cost more than the other colors.ColorWavelength (nm)Voltage Drop (V)Semiconductor MaterialInfrared> 760< 1.9Gallium ArsenideInfrared> 760< 1.9Aluminium Gallium ArsenideRed610 - 7601.6 -2.0Aluminium Gallium ArsenideRed610 - 7601.6 -2.0Gallium Arsenide PhosphideRed610 - 7601.6 -2.0Aluminium Gallium Indium PhosphideRed610 - 7601.6 -2.0Gallium PhosphideOrange590 - 6102.0 -2.1Gallium Arsenide PhosphideOrange590 - 6102.0 -2.1Aluminium Gallium Indium PhosphideOrange590 - 6102.0 -2.1Gallium PhosphideYellow570 - 5902.1 -2.2Gallium Arsenide PhosphideYellow570 - 5902.1 -2.2Aluminium Gallium Indium PhosphideYellow570 - 5902.1 -2.2Gallium PhosphideGreen500 - 5701.9 -4.0Gallium Indium PhosphideGreen500 - 5701.9 -4.0Aluminium Gallium Indium PhosphideGreen500 - 5701.9 -4.0Aluminium Gallium PhosphideGreen500 - 5701.9 -4.0Indium Gallium NitrideBlue450 - 5002.5 -3.7Zinc SelenideBlue450 - 5002.5 -3.7Indium Gallium NitrideBlue450 - 5002.5 -3.7Silicon CarbideBlue450 - 5002.5 -3.7SiliconViolet400 - 4502.8 -4.0Indium gallium NitridePurplemultiple types2.4 -3.7Dual Blue/Red LEDsPurplemultiple types2.4 -3.7Blue with Red PhosphorPurplemultiple types2.4 -3.7White with Purple Plasticultraviolet< 4003.1 -4.4Diamondultraviolet< 4003.1 -4.4Boron Nitrideultraviolet< 4003.1 -4.4Aluminium Nitrideultraviolet< 4003.1 -4.4Aluminium Gallium Nitrideultraviolet< 4003.1 -4.4Aluminium gallium Indium NitridePinkmultiple types3.3Blue with phosphorPinkmultiple types3.3Yellow with Red, Orange or Pink phosporPinkmultiple types3.3White with Pink pigmentWhiteBroad spectrum3.5Blue/UV diode with Yellow Phosphor How do LEDs work?A P-type semiconductor (which has a higher hole concentration) and an N-type semiconductor are combined to create LEDs, which are semiconductor light sources (larger electron concentration). The P-N junction's electrons and holes will join once more when a strong enough forward voltage is applied, releasing energy in the form of light.LEDs (Light Emitting Diodes) transform electrical energy directly into light as opposed to conventional light sources, which first convert electrical energy into heat before turning it into light. This results in efficient light creation with minimal electricity waste.LEDs Emit Light Types of LedsDual In-Line Package (DIP) LEDs:The first LED chips were DIP ones, which are what most people think of when considering LED lights. Despite being more established than its more recent counterparts, DIP LED chips are still in use and are more frequently seen integrated into electronics because of their small size. However, they are not very strong and can only provide a small amount of brightness.DIP LEDs Surface Mounted Diode (SMD) LEDs:These are likely the most popular sort of LED chip available; they are installed and soldered onto the circuit board. They are more adaptable when it comes to encasing them within smaller electronics or across other forms of lighting, such as strip lighting, because they are brighter than their DIP counterparts and are also smaller. Three diodes can fit on a single SMD chip, allowing you to produce a variety of colors and provide customers more options. The LED market has undergone this significant progress. SMD 3528 and SMD 5050, both of which measure 5mm in width, are the two most used SMD chip sizes.SMD LEDs Chip on Board (COB) LEDs:The most recent advancement in LED technology is represented by these chips. Out of the three, COB LED chips are the brightest since they can frequently fit nine or more diodes onto a single chip. In what ways does this affect LED lighting? First off, it increases lighting efficiency by improving brightness-to-energy output. They can therefore be utilized with a variety of various lighting types. However, it's important to keep in mind that a COB LED chip's circuitry prevents it from emitting a wide variety of colors.COB LEDs Calculating LEDs resistor valueTo limit the current flowing through an LED, a resistor must be connected in series with the LED; otherwise, the LED will burn out fairly immediately. R, the resistor's value, is determined by:R = (VS - VL) / IR = resistor value in ohms (ohm).VS = supply voltage.VL = LED voltage (2V, or 4V for blue and white LEDs).I = LED current in amps (A) The LED current needs to be lower than what your LED is capable of handling. Since the The maximum current for typical 5mm diameter LEDs is frequently 20mA; however, many circuits can work with 10mA or 15mA. Divide the mA current by 1000 to convert it to amps (A) for the calculation.If the projected value is unavailable, pick the nearest larger standard resistor value so that the current will be a little less than what you chose. If you choose a higher resistor value to reduce the current, the LED will be less bright (for example, to extend the battery life).The color of the LED affects the voltage VL of the LED. The voltage of red LEDs is the lowest; yellow and green have a somewhat higher value. The highest voltages are used in blue and white LEDs. You can use 2V for red, yellow, and green LEDs and 4V for blue and white LEDs for the majority of applications where the precise value is not crucial. According to Ohm's law, the resistor's resistance, R = V/I, is determined by:V = voltage across the resistor (= VS - VL in this case) I = the current through the resistorSo R = (VS - VL) / IResistor Value How to Test LED LightsStep One: Use a MultimeterGet a digital multimeter with a diode reading capability. Simple multimeters only measure voltages, amps, and ohms. A multimeter with a diode setting is required to test LED lighting. Mid-range to high-range multimeters, which are more likely to offer this capability than affordable versions, can be found online or at your neighborhood hardware store.Multimeter Step Two: Connect the black and red test leadsTo the outlets on the front of the multimeter, attach the red and black test leads. The positive charge is in the red lead. The input marked "COM" should be connected in with the black lead, which is the negative.Multimeter Connect Step Three: Select the diode setting on the multimeter's dialTo move your multimeter's front dial from the "off" position, turn it clockwise. Up till you reach the diode setting, keep twisting it. The diode setting may be represented by the diode circuit symbol if it is not labeled explicitly. The cathode and the anode of a diode are both visually represented by the diode symbol. In this digital multimeter dial picture, we need to set the multimeter’s dial on 14 to test diode.Multimeter dial Step Four: The red probe should be connected to the anode and the black probe to the cathodeThe cathode end of the LED, which is typically the shorter prong, should be touched with the black probe. The red probe should then be pressed against the anode, which is the longer prong. Ensure that the black probe is connected before the red probe because doing so can result in inaccurate readings. During this test, be sure the cathode and anode are not in contact with one another since this could prevent electricity from flowing through the LED light and affect your results. Throughout the test, the red and black probes must not come into contact. After making the connections, the LED ought should turn on.Diode test Step Five: Verify the reading on the digital multimeter displayA healthy LED light should show a voltage of about 1600 mV when the probes are in contact with the cathode and anode. If during the test there is no reading displayed on your screen, repeat the procedure to ensure that the connections were completed correctly. This can indicate that the LED light isn't functioning if the test was done correctly. The transformer needs to be changed if your supply does not provide any output voltage. LED lights need to be replaced if there is voltage present at the output. The warning of LEDs useIn general, it is not a good idea to connect multiple LEDs in parallel with just one resistor shared between them. Only the lowest voltage LED will light if the other LEDs require slightly different voltages, and the higher current running through it could damage the other LEDs. One resistor can be used to successfully link identical LEDs in parallel, but since resistors are so inexpensive and the current utilized is the same as connecting the LEDs separately, this rarely provides any significant benefit.LEDs in parallelInstead, we should do as follows: Connecting LEDs in seriesConnecting LEDs in series LEDs FAQWhat can the LEDs be applied to?LEDs (Light Emitting Diodes) are mostly used to illuminate items and even spaces. Due to its small size, low energy consumption, long lifespan, and versatility in terms of use in many applications, it is applied everywhere. LED usage and applications include TV backlighting. How many types that LEDs own?Fundamentally, LED lighting uses three major forms of LED technology: DIP, SMD, and COB. What is LED and how it works?When an electric current passes through a semiconductor device called a light-emitting diode (LED), the LED emits light. When current flows through an LED, the electrons and holes recombine and produce light. How long do LED lights last?The longer lifespan of LED lighting fixtures is one of its main benefits. The most durable LED light fixtures have been evaluated to survive as long as 100,000 hours, whereas incandescent light bulbs were designed to last roughly 1,000 hours. On average, LED light bulbs last at least 20 years before needing to be replaced. Which is not a benefit of LED?On a capital cost basis, LEDs are now more expensive (price per lumen) than the majority of conventional lighting solutions.