Hardware

= = =Personal computer hardware=

A [|personal computer] is made up of multiple physical components of **computer hardware**, upon which can be installed a system software called [|operating system] and a multitude of [|software] applications to perform the operator's desired functions. Though a PC comes in many different forms, a typical [|personal computer] consists of a [|case] or chassis in a tower shape (desktop), containing components such as a [|motherboard].

= =



Motherboard
= = The motherboard is the main component inside the case. It is a large rectangular board with integrated circuitry that connects the rest of the parts of the computer including the [|CPU], the [|RAM], the disk drives ([|CD], [|DVD], [|hard disk], or any others) as well as any peripherals connected via the ports or the expansion slots. Components directly attached to the motherboard include: = = = = = Power supply = = = ===A power supply unit (PSU) converts alternating current (AC) electric power to low-voltage DC power for the internal components of the computer. Some power supplies have a switch to change between 230 V and 115 V. Other models have automatic sensors that switch input voltage automatically, or are able to accept any voltage between those limits. Power supply units used in computers are nearly always [|switch mode power supplies (SMPS)]. The SMPS provides regulated direct current power at the several voltages required by the motherboard and accessories such as disk drives and cooling fans.=== = Removable media devices = = = = =
 * The **[|central processing unit] (**CPU**)** performs most of the calculations which enable a computer to function, and is sometimes referred to as the "brain" of the computer. It is usually [|cooled] by a heat sink and fan.
 * The **[|chip set]** mediates communication between the CPU and the other components of the system, including main memory.
 * **[|RAM]** (Random Access Memory) stores all running processes (applications) and the current running OS.
 * The **[|BIOS]** includes boot [|firmware] and power management. The **B**asic **I**nput **O**utput **S**ystem tasks are handled by [|operating system] drivers.
 * **Internal [|Buses]** connect the CPU to various internal components and to expansion cards for graphics and sound.
 * **Current**
 * The [|north bridge] memory controller, for RAM and PCI Express
 * [|PCI Express], for expansion cards such as graphics and physics processors, and high-end network interfaces
 * [|PCI], for other expansion cards
 * [|SATA], for disk drives
 * **Obsolete**
 * [|ATA] (superseded by SATA)
 * [|AGP] (superseded by PCI Express)
 * [|VLB] VESA Local Bus (superseded by AGP)
 * [|ISA] (expansion card slot format obsolete in PCs, but still used in industrial computers)
 * **External Bus Controllers** support ports for external peripherals. These ports may be controlled directly by the [|south bridge] I/O controller or based on expansion cards attached to the motherboard through the PCI bus.
 * [|USB]
 * [|FireWire]
 * [|eSATA]
 * [|SCSI]
 * [|CD] (compact disc) - the most common type of removable media, suitable for music and data.
 * [|CD-ROM Drive] - a device used for reading data from a CD.
 * [|CD Writer] - a device used for both reading and writing data to and from a CD.
 * [|DVD] (digital versatile disc) - a popular type of removable media that is the same dimensions as a CD but stores up to 12 times as much information. It is the most common way of transferring digital video, and is popular for data storage.
 * [|DVD-ROM Drive] - a device used for reading data from a DVD.
 * [|DVD Writer] - a device used for both reading and writing data to and from a DVD.
 * [|DVD-RAM Drive] - a device used for rapid writing and reading of data from a special type of DVD.
 * [|Blu-ray Disc] - a high-density optical disc format for data and high-definition video. Can store 70 times as much information as a CD.
 * [|BD-ROM Drive] - a device used for reading data from a Blu-ray disc.
 * [|BD Writer] - a device used for both reading and writing data to and from a Blu-ray disc.
 * [|HD DVD] - a discontinued competitor to the Blu-ray format.
 * [|Floppy disk] - an outdated storage device consisting of a thin disk of a flexible magnetic storage medium. Used today mainly for loading RAID drivers.
 * [|Iomega Zip drive] - an outdated medium-capacity removable disk storage system, first introduced by Iomega in 1994.
 * [|USB flash drive] - a flash memory data storage device integrated with a USB interface, typically small, lightweight, removable, and rewritable. Capacities vary, from hundreds of megabytes (in the same ballpark as CDs) to tens of gigabytes (surpassing, at great expense, Blu-ray discs).
 * [|Tape drive] - a device that reads and writes data on a magnetic tape, used for long term storage and backups.

Hardware that keeps data inside the computer for later use and remains persistent even when the computer has no power.
 * [|Hard disk] - for medium-term storage of data.
 * [|Solid-state drive] - a device similar to hard disk, but containing no moving parts and stores data in a digital format.
 * [|RAID array controller] - a device to manage several internal or external hard disks and optionally some peripherals in order to achieve performance or reliability improvement in what is called a RAID array.

Input and output peripherals
[|Input] and [|output] devices are typically housed externally to the main computer chassis. The following are either standard or very common to many computer systems. Wheel Mouse

Input
Main article: [|Input device]
 * [|Text] input devices
 * [|Keyboard] - a device to input text and characters by depressing buttons (referred to as keys).
 * [|Pointing devices]
 * [|Mouse] - a pointing device that detects two dimensional motion relative to its supporting surface.
 * [|Optical Mouse] - uses light to determine mouse motion.
 * [|Trackball] - a pointing device consisting of an exposed protruding ball housed in a socket that detects rotation about two axes.
 * [|Touchscreen] - senses the user pressing directly on the display
 * [|Gaming] devices
 * [|Joystick] - a control device that consists of a handheld stick that pivots around one end, to detect angles in two or three dimensions.
 * [|Game pad] - a hand held game controller that relies on the digits (especially thumbs) to provide input.
 * [|Game controller] - a specific type of controller specialized for certain gaming purposes.
 * [|Image], [|Video] input devices
 * [|Image scanner] - a device that provides input by analyzing images, printed text, handwriting, or an object.
 * [|Web cam] - a low resolution video camera used to provide visual input that can be easily transferred over the internet.
 * [|Audio] input devices
 * [|Microphone] - an acoustic sensor that provides input by converting sound into electrical signals.

Output
Main article: [|Output device]
 * [|Printer] - a device that produces a permanent human-readable text of graphic document.
 * [|Speakers] - typically a pair of devices (2 channels) which convert electrical signals into audio.
 * [|Headphones] - for a single user hearing the audio.
 * [|Monitor] - an electronic visual display with textual and graphical information from the computer.
 * [|CRT] - (Cathode Ray Tube) display
 * [|LCD] - (Liquid Crystal Display) as of 2010, it is the primary visual display for personal computers.

= = =**Hardware**= is a general term for the [|physical] [|artifacts] of a [|technology]. It may also mean the physical [|components] of a [|computer system], in the form of [|computer hardware]. Hardware historically meant the metal parts and fittings that were used to make wooden products stronger, more functional, longer lasting and easier to fabricate or assemble. [//[|citation needed]//] Modern [|hardware stores] typically sell equipment such as [|keys], [|locks], [|hinges], [|latches], [|corners], [|handles], [|wire], chains, [|plumbing] supplies, [|tools], [|utensils], [|cutlery] and [|machine] parts, especially when they are made of [|metal] hardwired
 * (1)** Electronic circuitry that is designed to perform a specific task. See hard coded.
 * (2)** Devices that are closely or tightly coupled. For example, a hardwired terminal is directly connected to a computer without going through a switched network.
 * (3)** Refers to fixed placement; for example, text and graphics that never change their location on a page. A "hardwired banner" is a banner ad that is not dynamically rotated with different page views.

=A **router**= is an electronic device that interconnects two or more [|computer networks], and selectively interchanges [|packets of data] between them. Each data packet contains address information that a router can use to determine if the source and destination are on the same network, or if the data packet must be transferred from one network to another. When multiple routers are used in a large collection of interconnected networks, the routers exchange information about target system addresses, so that each router can build up a table showing the preferred paths between any two systems on the interconnected networks. A router is a [|networking] device whose software and hardware are customized to the tasks of [|routing] and [|forwarding] information. A router has two or more network interfaces, which may be to different physical types of network (such as copper cables, fiber, or wireless) or different network standards. Each network interface is a specialized device that converts electric signals from one form to another. Routers connect two or more logical [|subnets], each having a different [|network address]. The subnets in the router do not necessarily map one-to-one to the physical interfaces of the router.[|[][|1][[[]|]]] The term "[|layer 3 switching]" is often used interchangeably the term "[|routing]". The term [|switching] is generally used to refer to data forwarding between two network devices with the same network address. This is also called layer 2 switching or LAN switching.



=**CD-ROM**= (pronounced [|/ˌsiːˌdiːˈrɒm/], an [|acronym] of "compact disc [|read-only memory]") is a pre-pressed [|compact disc] that contains [|data] accessible to, but not writable by, a computer for data storage and music playback, the 1985 developed by [|Sony] and [|Philips] adapted the format to hold any form of [|binary data].[|[][|2][[[]|]]] CD-ROMs are popularly used to distribute computer [|software], including games and multimedia applications, though any data can be stored (up to the capacity limit of a disc). Some CDs hold both computer data and audio with the latter capable of being played on a [|CD player], while data (such as software or digital video) is only usable on a computer (such as [|ISO 9660] format PC CD-ROMs). These are called [|enhanced CDs].

=A **hard disk drive**= (//hard disk//,[|[][|3][[[]|]]] //hard drive//,[|[][|4][[[]|]]] HDD) is a [|non-volatile storage] device for digital data. It features one or more rotating [|rigid platters] on a motor-driven [|spindle] within a metal case. Data is encoded magnetically by read/write heads that float on a cushion of air above the platters. Hard disk manufacturers quote disk capacity in [|SI]-standard powers of 1000, wherein a is 1000 gigabytes and a gigabyte is 1000 megabytes. With [|file systems] that report capacity in powers of 1024, available space appears somewhat [|less] than advertised capacity.

The first HDD was invented by [|IBM] in 1956. They have fallen in cost and physical size over the years while dramatically increasing capacity. Hard disk drives have been the dominant device for [|secondary storage] of data in [|general purpose computers] since the early 1960s.[|[][|5][[[]|]]] They have maintained this position because advances in their areal recording density have kept pace with the requirements for secondary storage.[|[][|5][[[]|]]] Form factors have also evolved over time from large standalone boxes to today's [|desktop] systems mainly with standardized 3.5-inch form factor drives, and [|mobile] systems mainly using 2.5-inch drives. Today's HDDs operate on high-speed serial interfaces, i.e., [|Serial ATA] (SATA) or [|Serial attached SCSI] (SAS).



=**Flash memory**= is a [|non-volatile] [|computer storage] chip that can be electrically erased and reprogrammed. It should not be confused with flash drives or pen drives which are USB storage device based on flash memory. It is primarily used in [|memory cards], [|USB flash drives], MP3 players like Ipods of Apple, T.Sonic of Transcend and [|solid-state drives] for general storage and transfer of data between computers and other digital products. It is a specific type of [|EEPROM] (electrically erasable programmable read-only memory) that is erased and programmed in large blocks; in early flash the entire chip had to be erased at once. Flash memory costs far less than byte-programmable EEPROM and therefore has become the dominant technology wherever a significant amount of non-volatile, [|solid state] storage is needed. Example applications include [|PDAs] (personal digital assistants), laptop computers, [|digital audio players], [|digital cameras] and [|mobile phones]. It has also gained popularity in console video game hardware, where it is often used instead of EEPROMs or battery-powered [|static RAM] (SRAM) for game save data.

=USB=
 * Universal Serial Bus** (**USB**) is a specification[|[][|1][[[]|]]] to establish communication between devices and a host controller (usually personal computers), developed and invented by [|Ajay Bhatt] while working for Intel.[|[][|2][[[]|]]][|[][|3][[[]|]]] USB has effectively replaced a variety of interfaces such as [|serial] and [|parallel ports]. USB can connect [|computer peripherals] such as [|mice], [|keyboards], [|digital cameras], [|printers], personal [|media players], [|flash drives], Network Adapters, and [|external hard drives]. For many of those devices, USB has become the standard connection method. USB was designed for [|personal computers], but it has become commonplace on other devices such as [|smartphones], [|PDAs] and [|video game consoles], and as a [|power cord]. As of 2008 [|[update]], there are about 2 billion USB devices sold per year, and approximately 6 billion total sold to date

=NIC=

A **network interface card** (**NIC**) is a hardware device that handles an [|interface] to a computer network and allows a network-capable device to access that network. The NIC has a [|ROM] chip that contains a unique number, the [|media access control (MAC) Address] burned into it. The MAC address identifies the device uniquely on the LAN. The NIC exists on the '[|Data Link Layer]' (Layer 2) of the [|OSI mode]

Purpose
A **network interface card**, **network adapter**, **network interface controller** (**NIC**), or **LAN adapter** is a [|computer hardware] component designed to allow computers to communicate over a [|computer network]. It is both an [|OSI layer] 1 ([|physical layer]) and layer 2 ([|data link layer]) device, as it provides physical access to a networking medium and provides a low-level addressing system through the use of [|MAC addresses]. It allows users to connect to each other either by using cables or wirelessly.



=**The central processing unit (CPU)**= ====is the portion of a [|computer] system that carries out the instructions of a [|computer program], and is the primary element carrying out the computer's functions. The central processing unit carries out each [|instruction] of the program in sequence, to perform the basic arithmetical, logical, and input/output operations of the system. This term has been in use in the computer industry at least since the early 1960s. [|[][|1][[[]|]]] The form, design and implementation of CPUs have changed dramatically since the earliest examples, but their fundamental operation remains much the same.====



An electronic component is any physical entity in an electronic system used 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 connected together, 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 complex groups as [|integrated circuits]. Some common electronic components are [|capacitors], [|inductors], [|resistors], [|diodes], [|transistors], etc. Components are often categorized as active (e.g. transistors and [|thyristors]) or [|passive] (e.g. resistors and capacitors).

Types of circuits
Circuits and components can be divided into two groups: analog and digital. A particular device may consist of circuitry that has one or the other or a mix of the two types.

Analog circuits
Main article: [|Analog electronics] 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. One rarely finds modern circuits that are entirely analog. These days analog circuitry may use digital or even microprocessor techniques to improve performance. This type of circuit is usually called "mixed signal" rather than analog or digital. 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 only outputs 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.

Digital circuits
Main article: [|Digital electronics] 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. Most digital circuits use two voltage levels labeled "Low"(0) and "High"(1). Often "Low" will be near zero volts and "High" will be at a higher level depending on the supply voltage in use. [|Ternary] (with three states) logic has been studied, and some prototype computers made. [|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: Highly integrated devices:
 * [|Logic gates]
 * [|Adders]
 * [|Binary Multipliers]
 * [|Flip-Flops]
 * [|Counters]
 * [|Registers]
 * [|Multiplexers]
 * [|Schmitt triggers]
 * [|Microprocessors]
 * [|Microcontrollers]
 * [|Application-specific integrated circuit] (ASIC)
 * [|Digital signal processor] (DSP)
 * [|Field-programmable gate array] (FPGA)

=Amplifier=

Generally, an **amplifier** or simply **amp**, is any [|device] that changes, usually increases, the [|amplitude] of a [|signal]. The relationship of the input to the output of an amplifier—usually expressed as a function of the input frequency—is called the [|transfer function] of the amplifier, and the magnitude of the transfer function is termed the [|gain]. In popular use, the term usually describes an [|electronic amplifier], in which the input "signal" is usually a voltage or a current. In [|audio] applications, amplifiers drive the [|loudspeakers] used in [|PA systems] to make the human voice louder or play recorded music. Amplifiers may be classified according to the input (source) they are designed to amplify (such as a [|guitar amplifier], to perform with an [|electric guitar]), the device they are intended to drive (such as a [|headphone amplifier]), the frequency range of the signals ([|Audio], [|IF], [|RF], and [|VHF] amplifiers, for example), whether they invert the signal ([|inverting amplifiers] and [|non-inverting amplifiers]), or the type of device used in the amplification ([|valve or tube] amplifiers, [|FET] amplifiers, etc.). A related device that emphasizes conversion of signals of one type to another (for example, a [|light] signal in [|photons] to a [|DC] signal in [|amperes]) is a [|transducer], a [|transformer], or a [|sensor]. However, none of these amplify [|power].

=Capacitor=

Modern capacitors, by a cm rule || A typical electrolytic capacitor A **capacitor** is a [|passive] [|electronic component] consisting of a pair of [|conductors] separated by a [|dielectric] (insulator). When there is a [|potential difference] (voltage) across the conductors, a static [|electric field] develops in the dielectric that stores [|energy] and produces a mechanical force between the conductors. An ideal capacitor is characterized by a single constant value, [|capacitance], measured in [|farads]. This is the ratio of the [|electric charge] on each conductor to the potential difference between them. Capacitors are widely used in electronic circuits for blocking [|direct current] while allowing [|alternating current] to pass, in filter networks, for smoothing the output of [|power supplies], in the [|resonant circuits] that tune radios to particular [|frequencies] and for many other purposes. The effect is greatest when there is a narrow separation between large areas of conductor, hence capacitor conductors are often called "plates", referring to an early means of construction. In practice the dielectric between the plates passes a small amount of [|leakage current] and also has an electric field strength limit, resulting in a [|breakdown voltage], while the conductors and [|leads] introduce an undesired [|inductance] and [|resistance].
 * ~ **Capacitor** ||
 * = [[image:http://upload.wikimedia.org/wikipedia/commons/thumb/8/86/Photo-SMDcapacitors.jpg/250px-Photo-SMDcapacitors.jpg width="250" height="187" caption="Photo-SMDcapacitors.jpg" link="http://en.wikipedia.org/wiki/File:Photo-SMDcapacitors.jpg"]]
 * ~ Type || [|Passive] ||
 * ~ Invented || [|Ewald Georg von Kleist] (October 1745) ||
 * ~ [|Electronic symbol] ||
 * = [[image:http://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/Capacitor_Symbol_alternative.svg/38px-Capacitor_Symbol_alternative.svg.png width="38" height="18" caption="Capacitor Symbol alternative.svg" link="http://en.wikipedia.org/wiki/File:Capacitor_Symbol_alternative.svg"]] ||

=Inductor=

A selection of low-value inductors || An **inductor** or a **reactor** is a [|passive] [|electrical component] that can store [|energy] in a [|magnetic field] created by the [|electric current] passing through it. An inductor's ability to store magnetic energy is measured by its [|inductance], in units of [|henries]. Typically an inductor is a conducting wire shaped as a coil, the loops helping to create a strong magnetic field inside the coil due to [|Ampere's Law]. Due to the time-varying magnetic field inside the coil, a voltage is induced, according to [|Faraday's law of electromagnetic induction], which by [|Lenz's Law] opposes the change in current that created it. Inductors are one of the basic electronic components used in electronics where current and voltage change with time, due to the ability of inductors to delay and reshape alternating currents. Inductors called chokes are used as parts of filters in power supplies or to block AC signals from passing through a circuit.
 * = [[image:http://upload.wikimedia.org/wikipedia/commons/thumb/a/a1/Electronic_component_inductors.jpg/225px-Electronic_component_inductors.jpg width="225" height="200" caption="Electronic component inductors.jpg" link="http://en.wikipedia.org/wiki/File:Electronic_component_inductors.jpg"]]
 * ~ Type || [|Passive] ||
 * ~ Working principle || [|Electromagnetic induction] ||
 * ~ First production || [|Michael Faraday] (1831) ||
 * ~ [|Electronic symbol] ||
 * = [[image:http://upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Inductor.svg/45px-Inductor.svg.png width="45" height="15" caption="Inductor.svg" link="http://en.wikipedia.org/wiki/File:Inductor.svg"]] ||

=Integrated circuit=

(Redirected from [|Integrated circuits]) Jump to: [|navigation], [|search] Integrated circuit of [|Atmel] Diopsis 740 [|System on Chip] showing memory blocks, logic and input/output pads around the periphery Microchips ([|EPROM] memory) with a transparent window, showing the integrated circuit inside. Note the fine silver-colored wires that connect the integrated circuit to the pins of the package. The window allows the memory contents of the chip to be erased, by exposure to strong [|ultraviolet light] in an eraser device. In [|electronics], an **integrated circuit** (also known as **IC**, **chip**, or **microchip**) is a miniaturized [|electronic circuit] (consisting mainly of [|semiconductor devices], as well as [|passive components]) that has been manufactured in the surface of a thin [|substrate] of [|semiconductor] material. Integrated circuits are used in almost all electronic equipment in use today and have revolutionized the world of electronics. [|Computers], [|cellular phones], and other [|digital] [|appliances] are now inextricable parts of the structure of modern societies, made possible by the low cost of production of integrated circuits. A [|hybrid integrated circuit] is a miniaturized electronic circuit constructed of individual semiconductor devices, as well as passive components, bonded to a substrate or circuit board. A monolithic integrated circuit is made of devices manufactured by diffusion of trace [|elements] into a single piece of semiconductor substrate, a chip.

=Diode=

In [|electronics], a **diode** is a two-[|terminal] [|electronic component] that conducts [|electric current] in only one direction. The term usually refers to a **semiconductor diode**, the most common type today. This is a crystalline piece of [|semiconductor] material connected to two electrical terminals.[|[][|1][|]] A **vacuum tube diode** (now little used except in some high-power technologies) is a [|vacuum tube] with two [|electrodes]: a [|plate] and a [|cathode]. The most common function of a diode is to allow an electric current to pass in one direction (called the diode's //forward// direction) while blocking current in the opposite direction (the //reverse// direction). Thus, the diode can be thought of as an electronic version of a [|check valve]. This unidirectional behavior is called [|rectification], and is used to convert [|alternating current] to [|direct current], and to extract [|modulation] from radio signals in radio receivers. However, diodes can have more complicated behavior than this simple on-off action. This is due to their complex [|non-linear] electrical characteristics, which can be tailored by varying the construction of their [|P-N junction]. These are exploited in special purpose diodes that perform many different functions. For example, specialized diodes are used to regulate voltage ([|Zener diodes]), to electronically tune radio and TV receivers ([|varactor diodes]), to generate [|radio frequency] [|oscillations] ([|tunnel diodes]), and to produce light ([|light emitting diodes]). Tunnel diodes exhibit [|negative resistance], which makes them useful in some types of circuits. Diodes were the first [|semiconductor electronic devices]. The discovery of crystals' [|rectifying] abilities was made by German physicist [|Ferdinand Braun] in 1874. The first semiconductor diodes, called [|cat's whisker diodes], developed around 1906, were made of mineral crystals such as [|galena]. Today most diodes are made of [|silicon], but other [|semiconductors] such as [|germanium] are sometimes used

From Wikipedia, the free encyclopedia Jump to: [|navigation], [|search] Figure 1: Closeup of a diode, showing the square shaped semiconductor crystal //(black object on left)//. Figure 2: Various semiconductor diodes. Bottom: A [|bridge rectifier]. In most diodes, a white or black painted band identifies the [|cathode] terminal, that is, the terminal which [|conventional current] flows out of when the diode is conducting. Figure 3: Structure of a [|vacuum tube] diode. The filament may be bare, or more commonly (as shown here), embedded within and insulated from an enclosing cathode

=Printed circuit board=

A **printed circuit board**, or **PCB**, is used to mechanically support and electrically connect [|electronic components] using [|conductive] pathways, tracks or signal traces [|etched] from copper sheets [|laminated] onto a non-conductive //substrate//. It is also referred to as **printed wiring board** (**PWB**) or **etched wiring board**. A PCB populated with electronic components is a **printed circuit assembly** (**PCA**), also known as a **printed circuit board assembly** (**PCBA**). PCBs are inexpensive, and can be highly reliable. They require much more layout effort and higher initial cost than either [|wire-wrapped] or [|point-to-point constructed] circuits, but are much cheaper and faster for high-volume production. Much of the electronics industry's PCB design, assembly, and quality control needs are set by standards that are published by the [|IPC] organization.