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Glossary

Definitions for jargon, scientific terms and phrases used at Harwin and across the connector and electronics industries.

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PC Tail
PCB

An electrical circuit constructed by printing or etching copper (or similar) onto an insulating material. The acronym PCB is short for Printed Circuit Board. Modern production methods mean that this process is completely automated. Designers use CAD software to design the layout of the component locations and the tracks that link them. The design is then converted to a machine-readable format, and the PCBs are then produced by industry standard machinery. This method eliminates variation in what can be very complicated circuits.

PCB Layout

Also know as a Land pattern, this is the layout of tracks that is required on the PCB for the attachment of a device with solder. Typically each part of the layout will be the same size or a little larger than the area on the device designed to be soldered. See also Space Constraints.

PCB Real Estate
PFOS, PFOA

Perfluorooctane sulfonates and Perfluorooctanoic acid. In the EU, manufacture and essentially all uses of PFOS are now prohibited under the EU Amendment 2006/122/ECOF – an amendment to the Dangerous Substances Directive 76/769/EEC. PFOA is still manufactured and is not currently prohibited under this legislation. However, both substances have shown in various reports to be carcinogenic and toxic. Harwin's general Environmental Legislation Statement includes a statement on these materials, and can be downloaded from our Environment section..

Pin Header

A particular type of male connector, a very basic construction. Consists of a carrier housing made from an insulating material, normally quite featureless, and an array of conductor pins (typically square or round cross-section) in a regular spaced pattern, on a regular pitch.

Pin Spacing

See Pitch

Pin-through
Pitch

The pitch of a connector is the distance between the center lines of two adjacent contacts. On a typical rectangular connector such as a pin header, this would be the same value between all adjacent pins, and becomes a defining element of the whole connector. Typical examples include 2.54mm (0.1") pitch and 1.27mm (0.05") pitch.

Plating Finish

Although copper and copper alloys make very good conductive elements within connectors and other devices, they also have their problems. Copper forms a layer of oxide (called verdigris) that is more insulating than copper, making the contact-to-contact resistance high. Also, bare copper would not solder very well. By electroplating the surface of the copper with various substances, oxidization is prevented and soldering is vastly improved.

The two most common plating finishes (the top layer of plating) in electronics are Tin and Gold. Tin gives an excellent solderable contact, whilst Gold gives the best wear resistance for mating surfaces. Neither are prone to oxidization that would cause a conductivity issue, and both are easy to electroplate. Nickel is also often added as an undercoat, to improve the bonding to the base metal and also to reduce effects such as tin whiskers.

Plating Thickness

As plating finishes are generally applied by electroplating, the thickness of the applied metal is normally very thin - in the order of microns (or micro-inches). Gold is often one of the thinnest plating finishes - very little is required to achieve reasonable wear, and a "flash" thickness (less than 0.05 microns or 2 micro-inches) is suitable for commercial low-price contacts. Thicker plating may be required for more rugged applications.

Polarization

An additional feature on a connector housing which mates into a complimentary feature on the opposing mating half. Often seen as a bump on one side, with a cutout on the other. This feature will make sure that the connectors are always mated in the same orientation to one another. In the case of rectangular connectors, it cannot be mated 180° round the wrong way. On a circular connector, it can only be mated at one angle, not a variety of angles (depending on pin layout).

Power Feed

The line (or lines) of current attached to a piece of equipment, giving that equipment the level of electricity it needs to operate or charge.

Power Transfer, Power Current

The flow of current through a device, typically referring to a higher level of current that will actually drive or power the device (as opposed to signal current, which is typically lower current and used to carry data).

Pre-crimped contacts, Pre-cabled contacts, Pre-wired contacts

An alternative to a fully manufactured cable assembly. An individual crimp or solder contact already attached to a set length of wire. This solution saves the customer from the cost of the crimping or soldering tools and operation, but still gives some flexibility in their final cable assembly.

Printed Circuit Board

See PCB

Product Change Notification

The notice sent to customers or other interested parties when a product undergoes a major change, or is declared for obsolescence.

Prototype

A development build of a product, that can be tested for certain characteristics, or to check the physical shape of an item, or any other steps that need to be checked before moving to production. Normally constructed by hand, and done in very low numbers.

Pull-Off Force

The amount of force, measured in Newtons (N), required to separate a cable from the contact to which it is crimped. A contact will have a Minimum pull-off force that is required to confirm it is a good crimp. As this is a destructive test, the testing would be done on additional product made at the same time as the production run. An acceptable result is also that the cable breaks rather than the crimp joint, as long as the minimum pull-off force is exceeded.