Editing Printed circuit board

A '''printed circuit board''' or '''PCB''' is a cost-effective, fast, tidy, compact and resilient way to manufacture electronic circuitry.

==Description==
Circuit pathways are etched out of a thin sheet of copper on a hard board, rather than being formed from individual loose wires; these pathways are referred to as "traces". A sealant layer is placed over the top of the copper; traditionally, this layer was green or brown, but bright colours are often seen now, red in particular.

[[:Category:Circuit components|Circuit components]] are soldered onto printed circuit boards. On a typical single-sided PCB, the components are placed onto one side, and the copper circuit traces are placed on the other. Many PCBs have copper traces on both sides to permit more complex circuitry to be arranged. The components may have legs that are pushed through holes punched in the PCB, or they may simply have small metal contacts, and be glued in place before being soldered; the latter approach is called "surface mount", and is commonly used for small components such as resistors and [[light-emitting diode]]s.

<gallery widths=250 heights=187>
File:Small PCB front.jpg                                 | Front of PCB with components
File:Small PCB rear.jpg                                  | Rear of PCB with circuit traces
</gallery>

==Switch mount==
In mechanical keyboards, the individual switches are all soldered onto a printed circuit board. Some switches are supported by the PCB alone, but better keyboards will include a sheet steel plate to support the switches. The exact method by which the switches are held in place is referred to as the [[switch mount]].

<gallery widths=250 heights=187>
File:MagitronicK156PCBleftangled.jpg                     | PCB-mounted [[Cherry MX Blue]] switches
File:MagitronicK156PCBright.jpg                          | PCB-mounted [[Cherry MX Blue]] switches
File:NTC 6153EN keyboard controller.jpg                  | Plate-mounted [[Simplified Alps Type IV switch]]es
File:Acer_switches_from_below.jpg                        | [[Contact mechanism#Membrane|Membrane]] keyboards only require a small PCB, to support the [[keyboard controller]] and connect to the membrane
</gallery>

==Examples==
<gallery widths=250 heights=187>
File:Phantom Teensy pinoutjpg.jpg                        | Section of the circuit design schematic for the [[Phantom]]
File:Apple M0116 circuit board.jpg                       | [[Alps Electric]]-made PCB in an [[Apple M0116]] keyboard
File:HID Liberation Device -- Line-up.JPG                | A batch of [[HID Liberation Device - Instructions|HID Liberation Device]] boards fresh from manufacturing
File:G80-9013HAD 008.jpg                                 | Complex controller and feature PCB from the [[Cherry G80-9013]] phoneboard
File:Marquardt military keyboard 7069-3111 trackball.jpg | Bright red PCB for the [[trackball]] in a [[Marquardt Military Keyboard 7069.3111|Marquardt Military Keyboard]]
</gallery>

==Manufacturers==
Notable PCB manufacturers include:

*[[Oak]] — used by various keyboard manufacturers including [[Wong's]]
*[[Sung Wei]] — PCB supplier to Datacomp

[[Category:Keyboard terms]]