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Circular Connectors Selection Guide

Circular connectors, multi-pin connectors, are used primarily for external interfacing. They can be used to transmit data, power electrical devices, or send electrical signals. Sometimes, circular connectors are designed to carry mixed signals. This is sometimes referred to to as a power-control connector. These connectors can be used to transmit both power and signals.
The term circular connector was used originally to refer to a circular plastic connection (CPC). These connectors, also called circular metal-shell connections (CMC), can be used in industrial applications when a secure and robust wire connection is required. These connectors can withstand harsh environments while providing a secure connection in industrial applications. You can also use circular connectors to refer to other types of connectors like DIN connectors or military connectors.

Circular metal-shell connectors, (CPC), and circular plastic connectors(CMC) were both developed by OEMs. These connectors can only be used with the OEM’s connectors. It is not possible to insert connectors that are made for different applications or by other OEMs due to their shell size, type or coupling, and contact arrangement.

MIL-SPEC connectors are military-grade connectors that conform to military specifications. Their design considers the protection of the connection from environmental factors. They can be used for military and aerospace purposes.

DIN connectors, which are multi-pin high frequency connectors, meet standards set by Deutsches Institut fur Normung. (DIN), a German national organisation for standardization. DIN connectors’ ends are round and notched. They have a metal skirt protecting them from damage.

Nano connectors and micro connectors have contact pitches of 0.025 inches (micro) and 0.05 inches (nano). They are straight- or right-angled, and can have one or two rows of plated contact.
Shell Sizing, Insert and Contacts

A circular connector is defined by its number of contacts and shell size. Each connector is designed to be used in the right application. Standard connectors are made to DIN and military standards. A variety of contacts can be accepted by the connector, and it may also come with a range insert options. Some connectors can be used without inserts and contacts. These connectors are used to protect the device and can be customized to suit specific applications.


The insert is an insulation body within the shell. It’s used to orientate electrical connections. Each insert is made to accommodate different sizes and types of contacts. They are designed to accept as many conductors or as many slots as possible. You don’t have to use every contact slot when wiring contacts. You can use a six conductor cable with an insert that supports more than six terminations if it meets the requirements for cable diameter. Sometimes it is preferable to occupy only a portion the available contact slots so that the plug can be oriented by aligning any missing contacts or blinds.
Electrical Contacts

Electrical contacts are soft and high-conductivity materials that resist oxidation. This material is used to conduct electrical current.
Shell Sizing

The shell is often used to describe size of connectors. The shell size can be described by a nominal number, usually followed by two digits. This number can be used to indicate the number 1/16th inch increments of the shell’s diameter.

Larger shells are usually used to house more power-consuming contacts. Inversely smaller shells house smaller sensors contacts. For flexibility in contact arrangement and size, intermediate shells are available. A range of cable diameters can be used with each shell.
Selection criteria

You should consider several factors when specifying circular connections: the connector type, gender and options for mounting, as well as performance criteria.

You can choose to have a male connector (with pins) and a female connector (with sockets). Pins that plug into a socket, or another receptacle are a male connector. A female connector includes sockets that have been aligned so they mesh with a pin type connector.


Connector termination refers to how the conductive materials mate with the contacts in the connector. There are many options for terminals. You have many options when it comes to termination.

Circular connectors can be mounted on a cable end or panel, circuit board, or other entry point. There are many options for attaching the connector. These include bulkheads or jam nuts, flanges, and inline cable mountings.
Current Ratings and Voltage

The maximum rated current or voltage describes the carrier signal the connector is capable of accommodating. The size and type contacts used determine the voltage and current ratings. Products that are used for electrical signals or sensors will have low amperage and voltage ratings. Power connectors have higher current and voltage ratings and require a larger load to power devices than other transmissions.

Current refers to the current (rate or flow of electricity) that a connector can carry. It is measured in amperes (A) and amps (A). The current rating of connectors is usually between 1A and 50A.
Voltage is the rating of the connector’s voltage in volts. There are five common ratings: 50V, 125V. 250V. and 600V.

Contact Size

Sometimes called “termination size”, contact size is also used to indicate the range or wire gauges that can be used with each contact. It can also be described as the contact’s actual diameter.

North America’s wire sizes are measured using the American Wire Gauge standard. The wire will be thinner if the AWG number is higher. AWG stands for Amount of Wire Throughput. This refers to the number of times the metal was passed through a wire machine. This reduces the diameter of the wire. This meant that 24-gauge wire was passed through the machine six times more often than 18 gauge wire.
Number of contacts

The number contacts is the number conductive elements in a connector which mate with an corresponding element to provide an electric path.