Electrical Connectors & Part Types List

Introduction

Electrical connectors, to put it simply, join two or more conductors together in a continuous and electrically conductive path. Regardless of their connection, application, or function, all electrical connectors have one objective, which is to create a path of electrical conduction between the joined conductors.

Connector Anatomy and Terminology

• Gender- Designates if a connector is something that plugs in or is plugged into. Connectors that plug into things are designated as ‘male,’ or plugs. Connectors that have things plugged into them are jacks, and designated ‘female.’
• Contact- Contacts are the metal parts that touch one another and form an electrical connection. Contacts can become soiled or oxidized and require occasional cleaning and maintenance.
• Polarity/Keying- Most connectors can only be connected in one orientation. This trait is called polarity, and connectors that are designed to prevent from being connected the wrong way are described as being “keyed,” or “polarized.”
• Pitch- The distance between the center of one contact and the center of the next. Families of contacts may look similar but differ in pitch. It is important to make sure the pitch matches when purchasing mating connectors!
• Mating cycles- Connecting and disconnecting connectors wears them out, giving them a lifespan known as mating cycles. A USB connector, for example, may have a lifespan of tens of thousands of mating cycles, while a board-to-board connector inside consumer electronics might only have tens of mating cycles in its lifespan.
• Mount-refers to several things; how a connector is mechanically attached (solder tab, surface mount, through hole) how a connector is mounted in use (panel mount, free-hanging, board mount) or what angle the connector is relative to its attachment (straight or right angle).
• Strain relief- Electrical connections are somewhat fragile when the connector is mounted to a board or cable. Strain relief is usually provided to transfer any forces acting on that connector to a more mechanically sound object.
• Connector Shell- The housing of the main connector.
• Pins and Sockets- Plug and socket connectors are made up of a male plug (with pin contacts) and a female socket (with socket contacts) with a matching shape and number of pins/sockets.

USB Connectors

USB (Universal Serial Bus) is a common interface that enables communication between devices and a host controller, such as a PC. USBs are used to connect many different devices, such as mice, keyboards, scanners, and printers. USB connectors come in two different types, peripheral and host. All USB connectors share similar traits.

• Polarization: A USB connector can only be inserted one way.
• Four contacts: All USB connectors have at least four contacts. Some have five, and USB 3.0 connectors may have even more. These are for power, ground, and data lines.
• USB connectors are shielded, such that a metal shell that is not part of the electrical circuit is provided.
• Robust power connection: Power pins need to connect before data pins, to avoid attempting to power the device over the data lines. USB connectors are designed to prevent this from happening.
• Molded strain relief: USB cables have plastic over-molding at the connector to prevent strain on the cable.

USB Types

• USB-A: Standard connector pair, consisting of a female host found on computers and hubs, and a male peripheral found on devices such as keyboards and mice.
• USB-B: Bulkier than USB-A, but more robust. Used in applications where size is not an issue, preferred means for providing a removable connector for USB connectivity.
• USB Mini: The first attempt to reduce the size of USB connections for smaller devices like MP3 players and cellphones.
• USB Micro: Released in 2007, designed for smaller devices and peripherals like cell phones and MP3 players. USB Micro was designed to replace USB Mini.
• USB C: The newest design of USB connectors, featuring a 24-contact pin design.

Audio Connectors

Audio connectors, as their name implies, transmit audio signals from one device to another. Two of the most common types of audio connectors are phone connectors and RCA connectors.

              “Phone” Type Connectors

Phone type connectors come in three sizes: ¼” (6.35mm) ⅛” (3.5mm) and 2.5mm. ¼” tip-sleeve jack connectors are used in audio and music, most commonly with electric guitars and amplifiers. ⅛” tip-ring-sleeve jacks (TRS) are common as the connector for headphones on MP3 players and computers. Finally, Texas Instruments graphing calculators use a 2.5mm tip-ring-ring-sleeve (TRRS) connector for serial programming. Tip-sleeve connector-types are not designed to carry power, and the lack of shielding makes them poor for carrying high-speed data, however.

RCA Connectors

RCA connectors have been used in home stereos for decades, ever since the design was first used by the company RCA for home phonographs in the 1940s. While the design has been supplanted by HDMI in the audio-visual realm, the ubiquity of RCA means that it will likely not be obsolete for years to come.

HDMI

HDMI (High Definition Multimedia Interface) is an audio/video interface that transmits video and audio data. HDMI connectors come in a 19-pin design with male plugs and female sockets and are used in DVD and Blu-Ray players, digital cameras, personal computers, and video game consoles.

D-Sub

A D-Sub contains two or more parallel rows of pins or sockets (depending on the gender of the connector) surrounded by a D-shaped metal shield that ensures correct orientation, provides mechanical support, and shields against electromagnetic interference. First introduced by Cannon in 1952, D-subs are rarely used for consumer electronics, but their sturdy construction makes them popular in industrial applications like foundries, factories, and mills.

Fiber Optic

An alternative to the metal wires used in other connectors, fiber optic cables use transparent and flexible fibers made from silica or plastic slightly thicker than human hair. These fibers transmit light from one end to the other and can transmit data over longer distances and at higher bandwidths than electrical cables.

Power

Many connectors carry power as well as data, but some are used specifically to power connected devices. These types include:

• Barrel: barrel connectors are found on low-cost consumer electronics that plug into the wall with bulky AC wall adapters.
• Molex: Molex connectors are used by computer hard drives, optical drives, and other internal peripherals. Capable of carrying up to eleven amps per pin, they are good for devices with high power requirements. Molex connectors are unique in that the female connector is on the cable, and the male connector is inside a plastic shell on the device that the cable plugs into.
• IEC: A generalized component name for a particular item, in this case PC power supplies. Like Molex, the female connector goes on the cable, while the male connector is on the device.

MIL-SPEC

Electrical and fiber-optic connectors used by the Department of Defense and various armed forces. Originally developed in the 1930’s, MIL-SPEC connectors consist of male plugs and female sockets like other connectors, but they are designed and manufactured to endure the harsh environment conditions and disruption that battle can cause (such as 100 g’s worth of shock).

At Aerospace Aces, owned and operated by ASAP Semiconductor, we sell electrical connectors from some of the top manufacturers around the world. Some of these manufacturers include Carling Technologies, Hubbell Electrical, and Micross Components.