printed circuit board

(redirected from PC board)
Also found in: Dictionary, Thesaurus, Wikipedia.

printed circuit board

[′print·əd ′sər·kət ‚bȯrd]
A flat board whose front contains slots for integrated circuit chips and connections for a variety of electronic components, and whose back is printed with electrically conductive pathways between the components. Also known as circuit board.

Printed Circuit Board


a board whose surfaces have printed current conductors with contact areas, which are used to connect components mounted on the boards according to the circuit diagram of a functional subassembly for electric or radio apparatus, and also have plated circuit holes and nonplated mounting holes. There are about 200 methods for making printed circuit boards; among the most important are the photochemical, photoelectrochemical, and offset-electrochemical methods. The methods differ in the means of producing the conductive coating or the form in which the pattern of the printed conductors is realized.

The dimensions of printed circuit boards, the position of the hole centers, and the hole diameters are standardized. The boards are 10–360 mm long, 10–240 mm wide, and 0.05–3.0 mm thick (depending on the rigidity required). The spacing of the coordinate grid for marking the holes is 2.5 mm or, less frequently, 1.25 mm, and the hole diameters range from 0.2 to 3 mm. A distinction is made among one-sided, two-sided, and multilayer boards (up to 15 layers). Multilayer boards are made by using extended leads, by metallizing the walls of through holes, by molding two-sided boards in pairs, or by layer-by-layer buildup. The material most often used for printed circuit boards are metal-clad and plain Micarta and fiberglass laminates, reinforced fluorine plastic, polystyrene, polyethylene terephthalate, polyamide, polycarbonate, and radioceramics.


Konstruirovanie i tekhnologiia pechatnykh plat. Moscow, 1973.


printed circuit board

(PCB) A thin board to which electronic components are fixed by solder. Component leads and integrated circuit pins may pass through holes ("vias") in the board or they may be surface mounted, in which case no holes are required (though they may still be used to connect different layers).

The simplest kind of PCB has components and wires on one side and interconnections (the printed circuit) on the other. PCBs may have components mounted on both sides and may have many internal layers, allowing more connections to fit in the same board area. Boards with internal conductor layers usually have "plated-through holes" to improve the electrical connection to the internal layers.

The connections are metal strips (usually copper). The pattern of connections is often produced using photo-resist and acid etching. Boards, especially those for high frequency circuits such as modern microprocessors, usually have one or more "ground planes" and "power planes" which are large areas of copper for greater current carrying ability.

A computer or other electronic system might be built from several PCBs, e.g. processor, memory, graphics controller, disk controller etc. These boards might all plug into a motherboard or backplane or be connected by a ribbon cable.

printed circuit board

A rigid, flat board that holds chips and other electronic components. The board is made of layers, typically two to 10, that interconnect components via copper pathways. The main printed circuit board (PCB) in a system is called a "system board" or "motherboard," while smaller ones that plug into the slots in the main board are called "boards" or "cards." See flexible circuit.

Etched Circuits
The "printed" circuit is an etched circuit. A copper foil is placed over a fiberglass or plastic base of each layer and covered with a photoresist. Light is beamed through a negative image of the circuit paths onto the photoresist, hardening the areas that will remain after etching. When passed through an acid bath, the unhardened areas are washed away. The finished layers are then glued together. A similar process creates the microminiaturized circuits on a chip (see chip).

Starting in the 1940s
Printed circuits were first used in the 1940s to connect discrete components together. By the 1960s, PCBs were widely used in all electronic systems, but still mostly connecting discrete components. Integrated circuits (chip) were emerging and added to the boards, and by the 1980s, PCBs were holding large quantities of chips. Today, printed circuit boards typically connect mostly chips with only a few discrete components, each chip containing from a few thousand up to hundreds of millions of transistors. See surface mount, via, discrete component, chip, card and motherboard.

Motherboard and Expansion Cards
This Baby AT board is an example of an early PC motherboard that used an ISA bus. It accepted both ISA and PCI cards containing peripheral controllers.

They Can Be Very Small
This WOW HD board from SRS, which has an audio jack for headphones on the end of the cable, creates a more dynamic audio experience for music listeners. The complex processing that takes place on this tiny board was unthinkable in the early days of computing. (Images courtesy of SRS Labs, Inc.,
References in periodicals archive ?
Without the use of screws or other threaded fastening hardware, they attach and space PC boards and subassemblies.
It is also needed for accurate characterization of receivers in a PC board environment.
They conform to the EIAJ ED-4702 industry standard ("Mechanical stress test methods for semiconductor surface mounting devices"), making them suited to PC boards already using surface-mount components.
The PC Board Layout Tools 386+ enable more control of the design process and the electrical environment of the design; easier creation and reuse of complex component shapes needed for high speed, high density designs; rapid connection of dense modules with the different pin spacings that are needed to package the functionality; and faster completion of the design, its verification and release to manufacturing.
OfficeCom joins the recently announced AudioCom as the newest member in a series of Spectrum PC boards targeted at PC multimedia.
ISLAMABAD, July 22, 2011 (Frontier Star): PC Board has constituted a six member Transaction Committee headed by a senior PC board member Iftikhar ul Haq with Mahmood Nawaz Shah, Farid Malik PC Board members, the Federal Secretaries Petroleum & Natural Resources, Privatization, Finance, Chairman SECP and MD PPL as its members Secondary Public Offering (SPO) of Pakistan Petroleum Limited (PPL).
ISLAMABAD, May 06, 2011 (Balochistan Times): A Pre-Qualification Committee (PQC) constituted by the PC Board jointly administered by the Privatization Commission (PC) and the Finance Division including members from SECP, M/o PNR, OGDCL, headed by a PC board member, has evaluated the RFP package during a presentations session by the interested parties (IPs).
Rather than having to exchange the entire PC board or solder new memory chips in place individually, users simply insert new SIMM modules.
NetFront was declared the overall winner from among several competing solutions in the "Browsers and Web Utilities" category by a Smartphone & Pocket PC Board of Experts.
According to a press release the PC Board will also review the implementation status of the decisions of the earlier meeting and discuss the matters pertaining to the hiring of Financial Advisor (FA) for the Oil & Gas Development Company Limited (OGDCL) Exchangeable Bonds, privatisation of Heavy Electrical Company (HEC) and possibilities of the Public Private Partnership (PPP) mode for the other Public Sector Entities (PSEs) on the active list.
The PC board formed various Transaction committees for these entities comprising on PC board members to monitor the progress of the process for ensuring utmost transparency and satisfaction of the all the respective stakeholders.
We've been applying our proven expertise in PC board and IC mass production techniques to this MIS industry-wide problem.