Circular connector

The term Circular Connector applies to any electrical connector possessing multipin interconnects with cylindrical contact housings and circular contact interface geometries. Circular connectors are selected for ease of engagement and disengagement, their ability to conveniently house different types of contacts, their wide range of allowable contact voltages and currents, their ease of environmental sealing and their rugged mechanical performance. In military, aerospace, and other high-reliability applications, the MIL-DTL-5015 and MIL-DTL-38999 are among the most commonly specified types. The primary disadvantage of the circular design is loss of panel space when used in arrays when compared to rectangular connectors.

In the early 1930s, Cannon (now ITT Interconnect Solutions) was contracted by Douglas Aircraft Company to develop connectors for use on the DC-1 and on the subsequent DC-2 and DC-3 aircraft platforms. During the late 1930s—with World War II on the horizon—Cannon began volume production of multi-contact electrical connectors that were used by virtually every aircraft builder in the United States. Cannon's Type "AN" (Army/Navy) series of connectors set the standard for modern military circular connector specifications now specified under the MIL-C-5015/MIL-DTL-5015 military specification.

The following Connector Terms and Definitions apply to circular connectors.

Accessories or Backshells are mechanical devices (e.g., strain reliefs, cable clamps, adapters, potting boots) that are threaded onto the rear connector accessory threads of plug or receptacle connectors to make up the total connector assembly.

Bayonet Mount interconnect mating designs use pins on the receptacle and ramps on the plug for quick-connect and disconnect coupling. Reverse Bayonet puts the pins on the plug and ramps on the receptacle.

Contact refers to the conductive element in a connector that mate mechanically and electrically to transmit signals and/or power across a connector interface. Crimp style contacts are the most common type found in high-reliability cylindrical connectors. Male contacts are sometimes referred to as leads, posts or pins, while Female contacts are universally known as sockets.

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