Electronics!

Your stationery is more cluttered than Warren Beatty's address book. The letterhead lists a fax number, e-mail addresses for two on-line services, and your Internet address, which spreads across the breadth of the letterhead and continues to the back. In essence, you have conceded that the first page of any letter you write IS letterhead.

You have never sat through an entire movie without having at least one device on your body beep or buzz.

You need to fill out a form that must be typewritten, but you can't because there isn't one typewriter in your house -- only computers with laser printers.

You think of the gadgets in your office as "friends," but you forget to send your father a birthday card.

You disdain people who use low baud rates.

When you go into a computer store, you eavesdrop on a salesperson talking with customers -- and you butt in to correct him and spend the next twenty minutes answering the customers' questions, while the salesperson stands by silently, nodding his head.

You use the phrase "digital compression" in a conversation without thinking how strange your mouth feels when you say it.

You constantly find yourself in groups of people to whom you say the phrase "digital compression." Everyone understands what you mean, and you are not surprised or disappointed that you don't have to explain it.

You know Bill Gates' e-mail address, but you have to look up your own social security number.

You stop saying "phone number" and replace it with "voice number," since we all know the majority of phone lines in any house are plugged into contraptions that talk to other contraptions.

You sign Christmas cards by putting :-) next to your signature.

Off the top of your head, you can think of nineteen keystroke symbols that are far more clever than :-).

You back up your data every day.

For the guys, your SO asks you to pick up some minipads for her at the store and you return with a rest for your mouse.

You think jokes about being unable to program a VCR are stupid.

On vacation, you are reading a computer manual and turning the pages faster than everyone else who is reading John Grisham novels.

The thought that a CD could refer to finance or music rarely enters your mind.

You are able to argue persuasively the Ross Perot's phrase "electronic town hall" makes more sense than the term "information superhighway," but you don't because, after all, the man still uses hand-drawn pie charts.

You go to computer trade shows and map out your path of the exhibit hall in advance. But you cannot give someone directions to your house without looking up the street names.

You would rather get more dots per inch than miles per gallon.

You become upset when a person calls you on the phone to sell you something, but you think it's okay for a computer to call and demand that you start pushing buttons on your telephone to receive more information about the product it is selling.

You know without a doubt that disks come in five-and-a-quarter and three-and-a-half-inch sizes.

Al Gore strikes you as an "intriguing" fellow.

You own a set of itty-bitty screw-drivers and you actually know where they are.

While contemporaries swap stories about their recent hernia surgeries, you compare mouse-induced index-finger strain with a nine-year-old.

You are so knowledgeable about technology that you feel secure enough to say "I don't know" when someone asks you a technology question instead of feeling compelled to make something up.

You rotate your screen savers more frequently than your automobile tires.

You have a functioning home copier machine, but every toaster you own turns bread into charcoal.

You have ended friendships because of irreconcilably different opinions about which is better -- the track ball or the track pad.

You email this message to your friends over the net. You'd never get around to showing it to them in person or reading it to them on the phone. In fact, you have probably never met most of these people face-to-face.

You cc this message to your SO.

You understand all the jokes in this message. If so, my friend, you are a geek. For your own good, go lie under a tree and write a haiku. And don't use a laptop.

Electronics

Electronics is the study of the flow of charge through various materials and devices such as, semiconductors, resistors, inductors, capacitors, nano-structures, and vacuum tubes. All applications of electronics involve the transmission of power and possibly information. Although considered to be a theoretical branch of physics, the design and construction of electronic circuits to solve practical problems is an essential technique in the fields of electronics engineering and computer engineering.

The study of new semiconductor devices and surrounding technology is sometimes considered a branch of physics. This article focuses on engineering aspects of electronics. Other important topics include electronic waste and occupational health impacts of semiconductor manufacturing.

Electronics Overview of electronic systems and circuits

Commercial digital voltmeter checking a prototypeElectronic systems are used to perform a wide variety of tasks. The main uses of electronic circuits are:

The controlling and processing of data

The conversion to/from and distribution of electric power

Both these applications involve the creation and/or detection of electromagnetic fields and electric currents. While electrical energy had been used for some time prior to the late 19th century to transmit data over telegraph and telephone lines, development in electronics grew exponentially after the advent of radio.

One way of looking at an electronic system is to divide it into 3 parts:

Inputs Electronic or mechanical sensors (or transducers). These devices take signals/information from external sources in the physical world (such as antennas or technology networks) and convert those signals/information into current/voltage or digital (high/low) signals within the system.

Signal processors These circuits serve to manipulate, interpret and transform inputted signals in order to make them useful for a desired application. Recently, complex signal processing has been accomplished with the use of Digital Signal Processors.

Outputs Actuators or other devices (such as transducers) that transform current/voltage signals back into useful physical form (e.g., by accomplishing a physical task such as rotating an electric motor).

For example, a television set contains these 3 parts. The television's input transforms a broadcast signal (received by an antenna or fed in through a cable) into a current/voltage signal that can be used by the device. Signal processing circuits inside the television extract information from this signal that dictates brightness, colour and sound level. Output devices then convert this information back into physical form. A cathode ray tube transforms electronic signals into a visible image on the screen. Magnet-driven speakers convert signals into audible sound.

Electronic devices and components

An electronic component is any physical entity in an electronic system whose intention is to affect the electrons or their associated fields in a desired manner consistent with the intended function of the electronic system. Components are generally intended to be in mutual electromechanical contact, usually by being soldered to a printed circuit board (PCB), to create an electronic circuit with a particular function (for example an amplifier, radio receiver, or oscillator). Components may be packaged singly or in more or less complex groups as integrated circuits.

Electronics Types of circuits

Electronics Analog circuits

Hitachi J100 adjustable frequency drive chassis.Most analog electronic appliances, such as radio receivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a continuous range of voltage as opposed to discrete levels as in digital circuits. The number of different analog circuits so far devised is huge, especially because a 'circuit' can be defined as anything from a single component, to systems containing thousands of components.

Analog circuits are sometimes called linear circuits although many non-linear effects are used in analog circuits such as mixers, modulators, etc. Good examples of analog circuits include vacuum tube and transistor amplifiers, operational amplifiers and oscillators.

Some analog circuitry these days may use digital or even microprocessor techniques to improve upon the basic performance of the circuit. This type of circuit is usually called "mixed signal."

Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non-linear operation. An example is the comparator which takes in a continuous range of voltage but puts out only one of two levels as in a digital circuit. Similarly, an overdriven transistor amplifier can take on the characteristics of a controlled switch having essentially two levels of output.

Electronics Digital circuits

Digital circuits are electric circuits based on a number of discrete voltage levels. Digital circuits are the most common physical representation of Boolean algebra and are the basis of all digital computers. To most engineers, the terms "digital circuit", "digital system" and "logic" are interchangeable in the context of digital circuits. In most cases the number of different states of a node is two, represented by two voltage levels labeled "Low" and "High". Often "Low" will be near zero volts and "High" will be at a higher level depending on the supply voltage in use.

Computers, electronic clocks, and programmable logic controllers (used to control industrial processes) are constructed of digital circuits. Digital Signal Processors are another example.

Building-blocks

Logic gates

Adders

Binary Multipliers

Flip-Flops

Counters

Registers

Multiplexers

Schmitt triggers

Highly integrated devices:

Microprocessors

Microcontrollers

Application-specific integrated circuit(ASIC)

Digital signal processor (DSP)

Field-programmable gate array (FPGA)

Electronics Mixed-signal circuits

Mixed-signal circuits refers to integrated circuits (ICs) which have both analog circuits and digital circuits combined on a single semiconductor die or on the same circuit board. Mixed-signal circuits are becoming increasingly common. Mixed circuits are usually used to control an analog device using digital logic, for example the speed of a motor. Analog to digital converters and digital to analog converters are the primary examples. Other examples are transmission gates and buffers.

Electronics Heat dissipation and thermal management

Heat generated by electronic circuitry must be dissipated to prevent immediate failure and improve long term reliability. Techniques for heat dissipation can include heatsinks and fans for air cooling, and other forms of computer cooling such as water cooling. These techniques use convection, conduction, & radiation of heat energy.

Electronic Noise

Noise is associated with all electronic circuits. Noise is defined as unwanted disturbances superposed on a useful signal that tend to obscure its information content. Noise is not the same as signal distortion caused by a circuit.

Electronic theory

Mathematical methods are integral to the study of electronics. To become proficient in electronics it is also necessary to become proficient in the mathematics of circuit analysis.

Circuit analysis is the study of methods of solving generally linear systems for unknown variables such as the voltage at a certain node or the current though a certain branch of a network. A common analytical tool for this is the SPICE circuit simulator.

Also important to electronics is the study and understanding of electromagnetic field theory.

Electronic test equipment

Electronic test equipment is used to create stimulus signals and capture responses from electronic Devices Under Test (DUTs). In this way, the proper operation of the DUT can be proven or faults in the device can be traced and repaired.

Practical electronics engineering and assembly requires the use of many different kinds of electronic test equipment ranging from the very simple and inexpensive (such as a test light consisting of just a light bulb and a test lead) to extremely complex and sophisticated such as Automatic Test Equipment.

Electronics Computer aided design (CAD)

Today's electronics engineers have the ability to design circuits using premanufactured building blocks such as power supplies, semiconductors (such as transistors), and integrated circuits. Electronic design automation software programs include schematic capture programs and pcb design programs. Popular names in the EDA software world are NI Multisim, Cadence (ORCAD), Eagle PCB and Schematic, Mentor (PADS PCB and LOGIC Schematic), Altium (Protel), LabCentre Electronics (Proteus) and many others.

Electronics Construction methods

Many different methods of connecting components have been used over the years. For instance, in the beginning point to point wiring with components attached to wooden breadboards were used to construct circuits. Cordwood construction and wire wraps were other methods used. Most modern day electronics now use printed circuit boards (made of FR4), and highly integrated circuits. Health and environmental concerns associated with electronics assembly have gained increased attention in recent years, especially for products destined to the European Union, with its Restriction of Hazardous Substances Directive (RoHS) and Waste Electrical and Electronic Equipment Directive (WEEE), which went into force in July 2006.