On 28th March 1979, at Three Mile Island nuclear power plant in USA, part of the core melted in the # 2 reactor. The TMI-2 reactor was destroyed. The cause of the accident was the little malfunction in the secondary cooling circuit which allowed temperature in the primary coolant to rise. This caused the reactor to shut down automatically. This situation developed because the level controls turned off the coolant to the reactor when they detected presence of cooling water near the top of the tank. The water at the top was not because of the tank got completely filled, it was because the water was too little in the tank that it got boiled and swelled up to the top of the tank.
Web Operating System is an internet service through which a user can access his computer data remotely anywhere on any computer and in any part of earth were internet is available. It has been termed as “Web Operating System” because they are present on the web and not on the computer of the user, all the data is being stored on the servers of the Web OS provider. Recently there was big roar on internet about the word “iCloud”. It was an introduction of one more operating system in the category of web operating systems. Web Operating systems (web OS) was introduced as a thought that one might be able to play with application, store data, and share it on the internet from anywhere in the world. So does a web OS do. Today web OS are capable of storing large amount of user data as large as 50 GB providing a very simplified and user friendly interface.
Let’s take a journey to the world of the electrical connectors. What is an electric connector? It is a simple, small size electro-mechanical device. It is basically use to connect two or circuits together. It is possible for the circuits to transfer power or signal through the connectors. Connectors have one more metallic structure inside it for electrical connections.The connectors always provide a temporary connection between the circuits. This temporary connection has so many advantages over the permanent connections. You can easily replace a particular circuit in a system; you can check the input or output of a circuit independently etc. Moreover the connector provides easy assembling and troubleshooting. An electrical connector is made of two things, conductors and insulators. Usually there is more than one conducting path for power or signal separated by insulators.A conductor as we all know allows electricity to flow through it, offers very low resistance. They are used to make physical contacts through which the electric current can flow through.
A reed switch consists of two ferromagnetic nickel-iron wires and specially shaped contact blades (reeds) positioned in a hermetically sealed glass capsule with a gap between them and in a protective atmosphere. The glass capsule is filled with inert gas to prevent activation of the contacts. The ruthenium or rhodium plated contact surfaces are isolated from the outside environment, which protects the contacts from contamination. Reed switches can be operated using a magnetic field generated by either a permanent magnet or current-carrying coil. They induce north (N) and south(S) poles on the reeds. The magnetic attractive force leads to closure of the reed contacts. Upon removal of the magnetic field, contact open again due to the elasticity of the reeds. There are Reed Switches which operate with permanent magnet, while there are Reed Switches operate with coils which can be magnetized by sending current through them.
Although a smaller shape, switches are essentially crucial for any device and hence, a design engineer should consider so many technical things related with a switch, while choosing a switch. Some of the few important terms that are taken care while configuring a switch are operating force, stroke, bounce time, various resistances, dielectric strength, power ratings etc.Alteration in these mentioned configurations affects the structure and working of switch in every possible manner. Hence, from a hardware designer to an installer, switch configuration plays an important part for any electrical device.The most common specifications found in the datasheet of switches are explained below.
In our day-to-day lives, how often do we encounter switches? Switches can be seen everywhere. For electronic and electrical system, they act as a physical interface to the real world. Be it a key of a keyboard or mobile or be it a knob on an electrical appliance or be it a miniature button used on the PCBs of embedded systems or be it a circuit breaker used on the power lines- all these are switches. We are in continuous interaction with switches without bothering about the manner it functions behind the scene?Switches are of different types, of different specifications and are selected and used in a particular application according to specific requirements. Subsequent sections will discuss the switches in detail.
During the last two decades, organic light-emitting diodes (OLEDs) have attracted considerable interest owing to their promising applications. They have already made inroads into the displays used for mobiles, PDAs and OLED TVs are also available in the market. Soon, OLEDs will be replacing incandescent and fluorescent lamps. Fig. 1: Image Showing a Regular…
RoHS is the acronym for Restriction of Hazardous Substances and is also known as “Lead free” (though incorrectly). RoHS directive is a European Union Directive 2002/95/EC and is applicable in all EU countries. The prime purpose of this directive is to restrict the use of hazardous substances in electric and electronic equipments with an objective of promoting environment friendly mechanism of recovery and disposal of wastes from electrical and electronic equipments. This directive restricts the use of six hazardous substances found in electrical and electronic products. Under RoHS, all electrical and electronic products destined for sale in the EU market after July 1, 2006 must pass RoHS compliance, i.e., they must be free of six hazardous substances identified by the directive. RoHS directive does not apply to spare parts for the repair or reuse of EEE put on the market before 1st Jul 2006.
Today, many of us are in the process of removing their CRT TVs and shopping for the new hype in the TV market –High Definition TVs. And if you happen to be one of them, you surely would have come across the term HDMI. Not only TV, HDMI port is available on home theatres, play stations, HD-DVDs and many others.The difference between a HDTVs and old TVs( also, now known as standard definition TVs) lies in the technology. Older TVs were analog, whereas HDTVs are digital. Older TVs used interlacing, aspect ratio of 4:3 and picture resolution of about 704 X 480 pixels. HDTVs use progressive scanning, aspect ratio of 16:9, picture resolutions up to 1920 X 1080 pixels. In other words, HDTVs use higher refresh rates, wider displays as well as enhanced picture resolution. What this implies is that HDTVs require higher amount of data to be processed and also at a faster rate compared to standard TVs.
When a communication is to be established, that too wirelessly, with a remote device, we typically employ optical radiations or radio waves or sometimes, acoustic waves (for underwater applications). These three types of wireless communications basically differ in their frequencies. All frequencies starting from frequency bands like LF, HF, VHF, UHF and so on, extending up to microwaves and millimeter waves are referred to as radio waves. Acoustic waves use ultrasonic portion of frequency spectrum. Optical Radiations use visible and infrared portion of the spectrum. Infrared sensors have been widely utilized for remote based applications such as in televisions etc. This article will detail with a Passive Infrared Sensor.
The Paris Air show is one of the biggest platforms for various airplane manufacturers to showcase the swiftness of their planes. Some of the valiant pilots of the world perform amazing stunts. These pilots are supported by the power of fast computing machinery in their airplanes. One of the critical parts of this computer assisted circuitry is the tilt sensor. A type of transducer, tilt sensor aids in giving information about the vertical as well as horizontal inclination of the airplane so that the pilot can understand how can he tackle the obstacles during the flight and perform the stunts
Body in motion usually experience vibration as well as shock. When a mobile falls on a floor, it is subjected to shock. When a vehicle moves on a bumpy road, it experiences vibrations. Likewise, there are many situations, where an object encounters shock and vibrations. Sometimes, they survive and at times, they get damaged. When delicate items like glass, crockery, etc. are packaged properly, they can withstand severe shock and vibrations. Whether a system will survive or not, how do we know this a priori? While some vibrations are desirable, some may be disturbing or even destructive. Hence, often a need is felt to understand the causes of vibrations and to develop methods to measure and prevent them.
Sensors are very important organs of any measurement system. They collect data from the surroundings/ physical parameter and provide electrical signal as the input to the systems. Amongst wide variety of sensors operating on different sensing principles and used in different applications, position sensors play an important role in different systems. Whether it is fly-by-wire aircraft systems, drive-by-wire cars, bullet trains taking round curves, injection molding machines, packaging machines, medical equipments, and so on, position sensors finds their applications, of course in different ways.
A transformer is an apparatus for converting electrical power in an ac system at one voltage or current into electrical power at some other voltage or current without the use of rotating parts. Transformers have been an essential component in electrical as well as electronic circuits. Apart from stepping up or stepping down the voltages, they are used for providing isolation, for impedance mismatch and so on. Development of new technologies has reduced the usage of transformers, but still they are quite vital in many applications.
Amazed by the electronic music of your favorite band? Mesmerized by the way suddenly an electric guitar goes as loud as the singer? Like most of know, there is an expert recording engineer present in the studio to make sure that music instruments and the voices make a perfect blend. A critical device that helps in creating this blend is an audio transformer. Works just like any other conventional transformer; audio transformers are designed to work at audio frequencies, i.e. between 20Hz to 20 KHz. interestingly, the initial need to design to such transformer was to enhance long distance voice communication. Now serving essentially for professional musicians, audio transformers stand as one electronic-audio component. This article will cover technical and applicative features of audio transformers explaining how they are different from the conventional counterparts
The dazzling Water Cube swimming arena at last summer’s Beijing Olympics was lit up by around half a million LEDs. Famous Bridges, buildings and hotels are opting LEDs for their exquisite night lighting and general illumination too. Why there is this sudden rage for the tiny LED? A little light emitter, a well renowned indicator that faithfully served in the display units of calculators, digital watches, and mobile phones for years is now geared up to take away the headache of efficient as well as Eco-friendly lighting.Yes, the tiny LED is all set to light our lives. It has taken a giant leap, from being a humble indicator to on the way to monopolize the lighting market. Years of research has brought LEDs to this advanced stage.
The $2.5 Billion rover of NASA, Curiosity is all set to take the tiniest detail of the planet Mars. The rover is designed to be highly precise in observing its ambient conditions including atmospheric pressure and the gravitational force. For this purpose, it’s Instrumental Control Unit or the ICU has been equipped with pressure sensors. These sensors will help in detecting the Dust Devils that are a characteristic of the planet and will also detail with the concentration of various gases in the atmosphere at various points. Let’s have a look on what makes a pressure sensor capable enough to perform such specific tasks and where else it can be used.A pressure sensor is a device which senses pressure and converts it into an analog electric signal whose magnitude depends upon the pressure applied. Since they convert pressure into an electrical signal, they are also termed as pressure transducers.
SPEED – a buzz word in today’s scenario, is a measure of “how fast”. Everybody is in a rat race and wants to run at the fastest speed. ‘Speed’ is used in variety of contexts and is measured using variety of methods in their own contexts.According to physics, speed is related to motion. Distance travelled by a moving body in a given time is called speed. Other related terms are angular speed, velocity, and angular velocity. Angular speed is the angular distance per unit time. (Linear) Velocity and angular velocity are vector quantities and are defined as displacement (linear/angular) per unit time.Speed is measured using different kinds of sensors operating on different principles. Subsequent sections will discuss various kinds of sensors used for measurement of speed (and related vector quantity, velocity).
Instruction Set Architecture(ISA) is important from user’s/ compilers perspective. Instruction Set Architecture is a ‘functional appearance to its immediate user/programmer’. ISA involves details like addressing modes, opcodes, registers, etc. Microarchitecture is important from the perspective of processor designer. Microarchitecture defines the logical structure or organisation that implements ISA. It involves details of pipelining stages, caches, physical registers, functional units, etc.Realization of hardware is important from the perspective of chip designer. Hardware is the actual “physical structure that embodies the implementation.” It involves micro-details of gates, transistors, wires, etc.Processors having identical ISA may be very different in organization. Processors with identical ISA and nearly identical organization are still not nearly identical.
Networking is playing vital role in current IT era where data distribution and access is critically As the use of communication between important. two or more entities increases the networking technologies need to be improved and refurbished over time. Similarly the transmission media, the heart of a network, has been changed with the time improving on the previous one. If you know a little bit about networking you surely have heard the term Ethernet which is currently the dominant network technology.Wide spread of the Ethernet technology made most of the offices, universities and buildings use the technology for establishment of local area networks (LANs).To understand what actually Ethernet is, we need to know about IEEE first which is a short of Institute of Electrical and Electronics Engineers. IEEE is a part of International Organization for Standardization (ISO) whose standard IEEE 802.3 is defined for Local Area Network.