A team of University of Wisconsin-Madison engineers has created the most functional flexible transistor in the world -- and with it, a fast, simple and inexpensive fabrication process that's easily scalable to the commercial level. It's an advance that could open the door to an increasingly interconnected world, enabling manufacturers to add "smart," wireless capabilities to any number of large or small products or objects -- like wearable sensors and computers for people and animals -- that curve, bend, stretch and move. Transistors are ubiquitous building blocks of modern electronics. The UW-Madison group's advance is a twist on a two-decade-old industry standard: a BiCMOS (bipolar complementary metal oxide semiconductor) thin-film transistor, which combines two very different technologies -- and speed, high current and low power dissipation in the form of heat and wasted energy -- all on one surface. As a result, these "mixed-signal" devices (with both analog and digital capabilities) deliver both brains and brawn and are the chip of choice for many of today's portable electronic devices, including cellphones. "The industry standard is very good," says Zhenqiang (Jack) Ma, the Lynn H. Matthias Professor and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison. "Now we can do the same things with our transistor -- but it can bend." Ma is a world leader in high-frequency flexible electronics. He and his collaborators described their advance in the inaugural issue of the journal Flexible Electronics. Making traditional BiCMOS flexible electronics is difficult, in part because the process takes several months and requires a multitude of delicate, high-temperature steps. Even a minor variation in temperature at any point could ruin all of the previous steps. Ma and his collaborators fabricated their flexible electronics on a single-crystal silicon nanomembrane on a single bendable piece of plastic. The secret to their success is their unique process, which eliminates many steps and slashes both the time and cost of fabricating the transistors. "In industry, they need to finish these in three months," he says. "We finished it in a week." He says his group's much simpler high-temperature process can scale to industry-level production right away. "The key is that parameters are important," he says. "One high-temperature step fixes everything -- like glue. Now, we have more powerful mixed-signal tools. Basically, the idea is for flexible electronics to expand with this. The platform is getting bigger." Ref.KY56-2SA1860KY45-EKMC1601113

Today I want to share an LED strobe design project I found in electronic-lab, which you can do it by yourself. Strobe provides regular flashes of light. Usually Strobes are designed using Xenon Tubes. Here is LED based simple solution that can be used as strobe for entertainment and events and also as warning signals. Project is based on PIC16F1825 micro-controller with two digit frequency display. Project provides TTL output signal, frequency 1Hz-25Hz, Tact switches provided to set the frequency. This project works along with DC Output Solid State Relay Features 1.Supply 4.5 to 5V DC2.Frequency 1Hz To 25Hz3.Easy Interface with Relay Board4.Easy Interface with Solid State Relay5.On Board Power LEDOn Board Output LED6.Onboard Switch to set the frequency7.2X7 Segment 0.5 Inch Display Applications 1.Strobe for Entertainment2.Traffic Signal3.Warning Signal4.Ambulance Warning Signals Schematic   Parts List Connections Photos Working Diagram Ref.PIC16F1825 

A Tomsk Polytechnic University study reveals how topological vortices found in low-dimensional materials can be both displaced and erased and restored again by the electrical field within nanoparticles. This may open exciting opportunities for memory devices or quantum computers in which information will be encrypted in the characteristics of topological vortices.(Vortices in nanoparticles exposed by the electrical field. Credit: Tomsk Polytechnic University (TPU))Scientists from TPU and international collaborators have discovered unusual self-organization of atoms in the volume of nanoparticles and have learned to control it via an electric field. Such controlled nanoparticles can be used to generate capacious non-volatile random access memory (NRAM), quantum computers and other next-generation electronics. The main author is Dmitriy Karpov, engineer of the Department of General Physics, TPU, who explains that in modern materials science, the defects of matter are divided into two large groups. The first group includes classical, well-studied defects, when atoms in matter are mechanically disordered, i.e., atoms are either removed or inserted into the lattice. In the other group, the spatial organization of the lattice itself changes and such defects are called topological. Topological defects can strongly influence matter, making it superfluid or superconductive, and therefore, it is very important to study them. Topological defects can be found only in low-dimensional materials—two-dimensional nanorods and nanofilms (just several atoms thick) and one-dimensional nanodots or nanoparticles, which are spherical particles consisting of several tens or hundreds of identical atoms. "One of the important topological defects is a topological vortex which looks like a discernible twisting caused by a small displacement of all atoms. The vortex core is a nanostrand which can be both displaced by the field, and erased and restored again within nanoparticles," explains Edwin Fohtung, Professor of Los Alamos National Laboratory and New Mexico State University . The scientists studied barium titanate nanoparticles whose internal structure was visualized with the help of penetrating X-ray radiation from the synchrotron Advanced Photon Source (Chicago, USA). They obtained an image of the volume of nanoparticles with a resolution of 18 nanometers, which enabled them to analyze the slightest changes in the structure. As a result, the researchers showed that an external electric field can displace the core of the topological vortex inside the nanoparticle, and when the field is removed, it returns to its original position. Modern components of electronics are gradually becoming smaller. This can significantly influence the efficiency of devices, which will be significantly reduced due to quantum effects. One way to circumvent these limitations is to use topological vortices. Thus, they can be used to generate high density NRAM or quantum computers in which information will be encrypted in the characteristics of topological vortices. "All in all, the possibility to control and adjust topological vortices in nanoparticles is important for the creation of new electronics," concludes Dmitriy Karpov. Further reading>>>Topological defectA topological defect can be proven to exist[when?] because the boundary conditions entail the existence of homotopically distinct solutions. Typically, this occurs because the boundary on which the conditions are specified has a non-trivial homotopy group which is preserved in differential equations; the solutions to the differential equations are then topologically distinct, and are classified by their homotopy class. Topological defects are not only stable against small perturbations, but cannot decay or be undone or be de-tangled, precisely because there is no continuous transformation that will map them (homotopically) to a uniform or "trivial" solution. Reference>>>KY259-BB910KY259-CXA1512MKY32-K9T1G08U0M-YIBO 

Today I want to share a project of making a simple automatic street light controller using relay and LDR I found in circuitdigest with you.   You have seen street light which automatically gets turned on in the night and gets turned off in the morning or day time, there are sensors who senses the light and control the light accordingly. These Street lights are an important project in smart cities.   So here in this project, we are going to make a Simple Automatic Street Light Controller Using Relay and LDR. This circuit is very simple circuit and can be built with Transistors and LDR, you don’t need any op-amp or 555 IC to trigger the AC load. Here we have used an AC bulb as street light. Some applications of this circuit are street light controlling, home/office light controlling, day and night indicators, etc.   Components Required:   Transistor BC547 -2 LDR (Light Dependent Resistor) Relay Resistor 1k 100k Potentiometer Power Supply 12v -1 Connecting wires Jumper wires Screw terminal Block 2 pin or 3 pin Bread Board or Perf Board 1n4007 Diode AC supply AC Load or Bulb   Here you may want to know: what is LDR? LDRs are made from semiconductor materials to enable them to have their light sensitive properties. There are many types but one material is popular and it is cadmium sulphide (CdS). These LDRs or PHOTO REISTORS works on the principle of “Photo Conductivity”. Now what this principle says is, whenever light falls on the surface of the LDR (in this case) the conductance of the element increases or in other words the resistance of the LDR falls when the light falls on the surface of the LDR. This property of the decrease in resistance for the LDR is achieved because it is a property of semiconductor material used on the surface. LDR (Light Dependent Resistor)   Circuit Diagram and Explanation:   Below is the circuit diagram of this Light sensing Street Light:       In this project, we have used an LDR (Light Dependent Resistor) which is responsible for detecting light and darkness. The resistance of LDR increases in darkness and reduces in presence of light. This circuit is same as a Dark Detector or Light Detector Circuit, only here we have replaced simple LED with a AC load, using a Relay. Two BC547 NPN transistors are used to drive the relay. Automatic Street Light circuit using LDR and relay   Whenever light falls over LDR its resistance get decreased and transistor Q1 turns ON and collector of this transistor goes LOW, and this makes the second transistor turns OFF due to getting a LOW signal at its base, so relay also remain turned OFF due to second transistor.   Now whenever LDR senses Darkness, mean no light, then transistor Q1 turned ON due to increase in the resistance of LDR which is responsible for voltage drop at the base of Q1. Due to a LOW signal at the Q1 base, Q2 transistor gets a HIGH signal from the collector of Q1 and turns ON the relay. Relay turned ON the AC load that is connected to relay. A 10K pot is also used for setting up the sensitivity of the circuit.   So this is how automatic Street Lights turns on in the night and turn off in the day, and below is the effect pictures. >>>>>                                                       > >>>>   Ref. KY56-BC547A KY32-1N4007  

Access to clean, safe water is one of the world’s pressing needs, yet today’s water distribution systems lose an average of 20 percent of their supply because of leaks. These leaks not only make shortages worse but also can cause serious structural damage to buildings and roads by undermining foundations, which is a great loss.Many property losses experienced by business owners involve water damage caused by leaky pipes. Water can be very destructive whether it seeps from a loose fitting or gushes from a ruptured main.Unfortunately, leak detection systems are expensive and slow to operate — and they don’t work well in systems that use wood, clay, or plastic pipes, which account for the majority of systems in the developing world. Now, a new system developed by researchers at MIT could provide a fast, inexpensive solution that can find even tiny leaks with pinpoint precision, no matter what the pipes are made of. The system, which has been under development and testing for nine years by professor of mechanical engineering Kamal Youcef-Toumi, graduate student You Wu, and two others, will be described in detail at the upcoming IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) in September. Meanwhile, the team is carrying out tests this summer on 12-inch concrete water-distribution pipes under the city of Monterrey, Mexico. The system uses a small, rubbery robotic device that looks something like an oversized badminton birdie. The device can be inserted into the water system through any fire hydrant. It then moves passively with the flow, logging its position as it goes. It detects even small variations in pressure by sensing the pull at the edges of its soft rubber skirt, which fills the diameter of of the pipe.(The fast, inexpensive robotic device that developed by engineers from MIT can find even tiny leaks in pipes with pinpoint precision, no matter what the pipes are made of.)This device contains two parts: "skirt" sensor and soft body drone. It is then retrieved using a net through another hydrant, and its data is uploaded. No digging is required, and there is no need for any interruption of the water service. In addition to the passive device that is pushed by the water flow, the team also produced an active version that can control its motion.Monterrey itself has a strong incentive to take part in this study, since it loses an estimated 40 percent of its water supply to leaks every year, costing the city about $80 million in lost revenue. Leaks can also lead to contamination of the water supply when polluted water backs up into the distribution pipes. The MIT team, called PipeGuard, intends to commercialize its robotic detection system to help alleviate such losses. In Saudi Arabia, where most drinking water is provided through expensive desalination plants, some 33 percent is lost through leakage. That’s why that desert nation’s King Fahd University of Petroleum and Minerals has sponsored and collaborated on much of the MIT team’s work, including successful field tests there earlier this year that resulted in some further design improvements to the system, Youcef-Toumi says. DKNY CEO Caroline Brown, said “PipeGuard has created a simple, pragmatic and elegant solution to a complex problem. … This robot is a great example of utilizing smart design to simplify complexity and maximize efficiency.”

Modern life will be almost unthinkable without transistors. They are the ubiquitous building blocks of all electronic devices: each computer chip contains billions of them. However, as the chips become smaller and smaller, the current 3D field-electronic transistors (FETs) are reaching their efficiency limit. A research team at the Center for Artificial Low Dimensional Electronic Systems, within the Institute for Basic Science (IBS), has developed the first 2D electronic circuit (FET) made of a single material. Published on Nature Nanotechnology, this study shows a new method to make metal and semiconductor from the same material in order to manifacture 2D FETs. Faster electronic device architectures are in the offing with the unveiling of the world’s first fully two-dimensional field-effect transistor (FET) by researchers with Lawrence Berkeley National Laboratory (Berkeley Lab). Unlike conventional FETs made from silicon, these 2D FETs suffer no performance drop-off under high voltages and provide high electron mobility, even when scaled to a monolayer in thickness.（Berkeley Lab researchers fabricated the first fully 2D field-effect transistor from layers of molybdenum disulfide, hexagonal boron nitride and graphene held together by van der Waals bonding.） Ali Javey, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a UC Berkeley professor of electrical engineering and computer science, led this research in which 2D heterostructures were fabricated from layers of a transition metal dichalcogenide, hexagonal boron nitride and graphene stacked via van der Waals interactions. In simple terms, FETs can be thought as high-speed switches, composed of two metal electrodes and a semiconducting channel in between. Electrons (or holes) move from the source electrode to the drain electrode, flowing through the channel. While 3D FETs have been scaled down to nanoscale dimensions successfully, their physical limitations are starting to emerge. Short semiconductor channel lengths lead to a decrease in performance: some electrons (or holes) are able to flow between the electrodes even when they should not, causing heat and efficiency reduction. To overcome this performance degradation, transistor channels have to be made with nanometer-scale thin materials. However, even thin 3D materials are not good enough, as unpaired electrons, part of the so-called "dangling bonds" at the surface interfere with the flowing electrons, leading to scattering. FETs, so-called because an electrical signal sent through one electrode creates an electrical current throughout the device, are one of the pillars of the electronics industry, ubiquitous to computers, cell phones, tablets, pads and virtually every other widely used electronic device. All FETs are comprised of gate, source and drain electrodes connected by a channel through which a charge-carrier – either electrons or holes – flow. Mismatches between the crystal structure and atomic lattices of these individual components result in rough surfaces – often with dangling chemical bonds – that degrade charge-carrier mobility, especially at high electrical fields. Passing from thin 3D FETs to 2D FETs can overcome these problems and bring in new attractive properties. "FETs made from 2D semiconductors are free from short-channel effects because all electrons are confined in naturally atomically thin channels, free of dangling bonds at the surface," explains Ji Ho Sung, first author of the study. Moreover, single- and few-layer form of layered 2D materials have a wide range of electrical and tunable optical properties, atomic-scale thickness, mechanical flexibility and large bandgaps (1~2 eV).    Researchers produced the first 2D field-effect transistor (FET) made of a single materialThe major issue for 2D FET transistors is the existence of a large contact resistance at the interface between the 2D semiconductor and any bulk metal. To address this, the team devised a new technique to produce 2D transistors with semiconductor and metal made of the same chemical compound, molybdenum telluride (MoTe2). It is a polymorphic material, meaning that it can be used both as metal and as semiconductor. Contact resistance at the interface between the semiconductor and metallic MoTe2 is shown to be very low. Barrier height was lowered by a factor of 7, from 150meV to 22meV. IBS scientists used the chemical vapor deposition (CVD) technique to build high quality metallic or semiconducting MoTe2 crystals. The polymorphism is controlled by the temperature inside a hot-walled quartz-tube furnace filled with NaCl vapor: 710°C to obtain metal and 670°C for a semiconductor. The scientists also manufactured larger scale structures using stripes of tungsten diselenide (WSe2) alternated with tungsten ditelluride (WTe2). They first created a thin layer of semiconducting WSe2 with chemical vapor deposition, then scraped out some stripes and grew metallic WTe2 on its place. It is anticipated that in the future, it would be possible to realize an even smaller contact resistance, reaching the theoretical quantum limit, which is regarded as a major issue in the study of 2D materials, including graphene and other transition metal dichalcogenide materials. Ref.FDMT800120DCSTP160N3LL