Coaxial power connector

A hollow plug (also DC or DC connector) is a two pin connector, which is used to supply power to battery-powered small devices, to load the stored in these devices battery pack or power other self-powered small devices with an external power supply. One type of hollow plug is to be found in Japanese electronic equipment, is the EIAJ connector.

General

Due to the open construction hollow plugs are approved for operation with safe low voltage. Compared with plugs they have the advantage that there is no short circuit can occur through the inner contact under conditions of normal use.

Typical applications are in portable audio devices such as MP3 and CD players, as well as chargers, such as batteries for camcorders or electrically operated toys.

The pin assignment of the hollow plug is not standardized. The polarity can thus be interchanged depending on the device. As a de facto standard, however, the occupancy Plus has prevailed on the inner conductor. Nevertheless, allow many universal wall socket parts interchanging the polarity by reversing the connection cable or via a switch. If the polarity for both the connected device and can destroy the power supply ( in extreme cases ). Often located on the terminals for lead assignment in the form of a pictogram.

Also the dimensions of the plug are not standardized, which is why most universal AC adapters supplied with a whole battery of different adapters that allow the power supply for most devices is appropriate. Some barrel connector also have a notch that allows a snapping into corresponding sockets, others do not lock and can inadvertently slip out of its socket. By far the most common size variants are:

  • 5.5 mm / 2.5 mm ( Outside-/Inside diameter ) and
  • 5.5 mm / 2.1 mm

Connector with 2.5 mm inner diameter fit mostly in sockets with 2.1 mm pin, but sometimes give a bad connection. Smaller sizes are:

  • 5.0 mm / 2.0 mm (2.1? )
  • 4.8 mm / 1.7 mm (esp. at Hewlett -Packard Laptop Computers )
  • 4.0 mm / 1.7 mm
  • 3.5 mm / 1.35 mm
  • 2.35 mm / 0.7 mm

Chance found on network devices and jack (instead of hollow plug) with 3.5 or 2.5 mm diameter.

Barrel connector can also be used in devices that are supplied with alternating low voltage.

TRS and hollow plug adapter for Universal car power adapter

Cannon plug on a SNES power supply

5-mm Sockets. Pin diameter left 2.5 mm, right 2.1 mm

Kontaktierungsfunktion

An external spring inside the jack pushes the plug against the center pin. Therefore, the effective contact areas of the connector are much smaller than suggested.

Sockets for higher currents have similar to a banana plug spring- split center pins; then contacting the outer surface can also be done at several points all around. The plug must fit exactly and has lower manufacturing tolerances.

Special designs

For the power supply of notebooks manufacturer-specific special forms are often used. Often, the center pin is annular, and the plug has a ( electrically non-functional ) center pin. Such connectors make the plug partner unmistakable, however, complicate the replacement.

Some barrel connector have a resilient insulating sleeve for the external contact. This type is intended for use in motor vehicles, where the supplied low voltage is not isolated. A short circuit of the external contact with the body can (if positive pole outside or Plus on body - - on historical vehicles ) to unwanted ground currents or even lead to a short circuit.

  • Connectors
Rechargeable battery Hewlett-Packard
223672
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