Military MIL Grade Connectors: Specifications, Terminals, Coupling Types, Features

Military MIL Grade connectors, also called MIL-SPEC connectors, are shell-type connectors designed to work in harsh environmental factors to meet all the military and aerospace application requirements. The Military connectors are referred to as MIL-STD or MIL-SPEC connectors whereas the type AN (Army-Navy) connector sets the standard for modern-day connectors. 

The connectors have a plug and receptacle for mating and this pair is equipped with pin and socket contacts also called male, female contacts respectively.

Specifications

Certain product parameters must be considered when specifying Military MIL grade connectors which include:

1. Number of Contacts: It is the number of conductive elements present in a MIL-SPEC connector. Their role is to provide the electrical path when two types of contacts, either pins or sockets, are connected.
2. Contact Type: There are two contact types i.e., Pin (Male) and Socket (Female).
3. Coupling Types: Different types of couplings are Bayonet, Breech Lock, Push/Pull (Ball Detent Coupling), Spring Rack/Quick Connect, and Threaded.
4. Contact Size: It is the designation used to differentiate one contact from another, typically denoted using AWG (American Wire Gauge).

Shell Specifications

1. Shell Gender: It is denoted as male or female and male “plugs” are also called free connectors or headers. The plug is attached to a cable and is easily movable. They are inserted into female connectors such as receptacles, jacks, outlets, etc. to make circuit connectors. 
2. Shell Size: The most widely recognized shell sizes are accessible in .0625" increments starting at shell size 8 (.50) to shell size 36 (2.25). MIL grade connectors, which use threads to join backshells, are typically equivalent to .062 of the connector shell size.
3. Shell Style: The main housing of the connector is called Shell. The MIL-SPEC circular connectors have a cylindrical shell, available in various sizes starting around .375" in diameter.

Terminals

It is a device that terminates the connection. To make electrical connections terminals are very important and can be attached to posts, studs, or other types of conductors. The variety of terminal devices includes screws, cage clamps, wire soldered onto a PCB, lugs, IDC (Insulation Displacement Connectors), lanyard release, solder cup or solder, tabs, Through-hole technology (THT), wire wrap, and crimping.

Special Features

The military MIL grade connectors have various other additional features which help them in performing for the desired applications. These features are:

1. Integrated filter/magnetics- As these military connectors are used in harsh environments, there is always a threat of unwanted signals that can cause unexpected behavior of the appliances. To avoid such a situation, these connectors have filters that provide isolation, signal conditioning, and filtering by protecting them from unwanted signals and magnetics.
2. Underwater Use- When used with Navy appliances, the connectors have to face water pressure and have the threat of moisture and humidity. The connectors are sealed so tightly that no external exchange can take place under the water.
3. Hermetically Sealed- That means no internal moisture leakage is allowed in the connectors when they are hermetically sealed.
4. Environment Resistant- They are designed to survive in harsh environmental conditions like chemicals, sun, dirt, etc.