Connector Basics

Author: Evelyn y

Mar. 07, 2024

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Connector Terminology

Before we get started discussing some commonly used connectors, let's explore the terminology used to describe connectors.

Gender

Gender - The gender of a connector refers to whether it plugs in or is plugged into and is typically male or female, respectively (kids, ask your parents for a more thorough explanation). Unfortunately, there are cases where a connector may be referred to as "male" when it would appear to be female; in the examples section, we'll point a few of those out as we discuss individual component types and explain why that's the case.

Male (left) and female 2.0mm PH series JST connectors. In this case, gender is determined by the individual conductor.

Polarity

Polarity - Most connectors can only be connected in one orientation. This trait is called polarity, and connectors which have some means to prevent them being connected wrong are said to be polarized, or sometimes keyed.

A polarized North American wall plug. By having two different widths for the plug blades, the plug will only go into the outlet one way.

Contact

Contact - Contacts are the business portion of the connector. They are the metal parts which touch each other, forming an electrical connection. This is also where problems occur: the contacts can become soiled or oxidized, or the springiness required to hold the contacts together may fade with time.

The contacts on this connector are clearly visible.

Pitch

Pitch - Many connectors consist of an array of contacts in a repeated pattern. The pitch of the connector is the distance from the center of one contact to the center of the next. This is important, because there are many families of contacts which look very similar but may differ in pitch, making it difficult to know that you are purchasing the right mating connector.

The pitch of the pins on the headers on a standard Arduino is .1".

Mating Cycles

Mating cycles - Connectors have a finite life, and connecting and disconnecting them is what wears them out. Datasheets usually present that information in terms of mating cycles, and it varies widely from one technology to another. A USB connector may have a lifetime in the thousands or tens of thousands of cycles, while a board-to-board connector designed for use inside of consumer electronics may be limited to tens of cycles. It's important that you select a connector with a suitable life for the application.

Mount

Mount - This one has the potential for being confusing. The term "mount" can refer to several things: how the connector is mounted in use (panel mount, free-hanging, board mount), what the angle of the connector is relative to its attachment (straight or right-angle), or how it is mechanically attached (solder tab, surface mount, through hole). We'll discuss this more in the examples section for each individual connector.

A comparison of three different methods of mounting the same barrel connector: (left to right) board mount, inline cable mount, and panel mount.

Strain Relief

Strain relief - When a connector mounts to a board or cable, the electrical connections tend to be somewhat fragile. It is typical to provide some kind of strain relief to transfer any forces acting on that connector to a more mechanically sound object than the fragile electrical connections. Again, there will be some good examples of this later on.

This 1/8" headphone jack comes with a strain relief "boot" slid over the cable to prevent forces on the cable from being transmitted directly to the electrical joints.

Other Connectors

RJ-type Modular Connectors

Registered jack connectors are standard for telecommunications equipment into a local exchange. The names one normally hears associated with them (RJ45, RJ12, etc) are not necessarily correct, as the RJ designator is a based on a combination of the number of positions, the number of conductors actually present, and the wiring pattern. For example, while the ends of a standard ethernet cable are usually referred to as "RJ45", RJ45 actually implies not only an 8 position, 8 conductor modular jack, it also implies that it is wired for ethernet.

These modular connectors can be very useful, since they combine ready availability, multiple conductors, moderate flexibility, low cost, and moderate current carrying capacity. While not originally intended to deliver a great deal of power, these cables can be used to deliver data and a couple of hundred milliamps from one device to another. Care should be taken to ensure that jacks provided for applications like this are not connected to conventional ethernet ports, as damage will result.

A standard 8p8c (8-position, 8-conductor) "RJ45" modular jack . Be aware that if you intend to use this type of jack to pass DC signals and power, you must avoid using connectors with built-in signal transformers

D-sub Type Connectors

Named for the shape of their shell, D-subminiature connectors are a classic standard in the computing world. There are four very common varieties of this connector: DA-15, DB-25, DE-15, and DE-9. The pin number indicates the number of connections provided, and the letter combination indicates the size of the shell. Thus, DE-15 and DE-9 have the same shell size, but a different number of connections.

Female DE-9 board-mount connector . Gender is defined by the pins or sockets associated with each signal, not the connector as a whole, making this connector female despite the fact that it effectively inserts into the shell of the mating connector.

DB-25 and DE-9 are the most useful to the hardware hacker; many desktop computers still include at least one DE-9 serial port, and often one DB-25 parallel port. Cables terminated with DE-9 and DB-25 connectors are widely available, too. As with the modular connector above, these can be used to provide power and point-to-point communications between two devices. Again, since the common usage of these cables does not include power transmission, it is very important that any repurposing of the cables be done cautiously, as a non-standard device plugged into a standard port can easily cause damage.

Today, most workers use at least three separate devices to communicate. The ability to connect with anyone, anywhere, is essential to businesses in the modern era. When communication issues occur, it affects production, customer satisfaction, and so much more.

When communication issues occur, they may be caused by electronic or electrical connectors—hereinafter called electronic. If they are worn down or made in a less than ideal way, they can affect your ability to connect with the world around you.

Whether you're a manufacturer, a business owner, or someone who just wants to figure out why your device is not working right, this guide is for you.

Here's a rundown of what electronic connectors are and how they are used in communication applications.

What are Electronic Connectors?

Electronic connectors bridge the communication between blocked or isolated circuits. This allows a smooth flow between two active devices, so the circuit can better act on its function.

Electronic connectors come in a range of shapes and sizes. This allows them to fit a wide range of objects, frequencies, power levels, and settings. No matter what they are being used for, they are essential for a continuous, reliable current.

Parts of an Electronic Connector

The main parts of a connector consist of a contact, insulator, and shell if part of the connector.

Some types of connectors may also require accessories, which fall into one of two types. Installation accessories include parts such as screws, nuts, and spring rings. Structural accessories include parts like:

Guiding pins
Connection rings
Cable clamps
Strain reliefs
Grommets & gaskets

The contact is the central part of the connector. It allows the electronic connection to be complete.

The insulator is the base or insert of a connector. Its purpose is to make sure contacts are properly placed aligned, and spaced. This ensures there is good insulation between contacts and between contacts and housing.

The material of an insulator or housing needs to be able to resist and withstand the voltage of a circuit. This will help encourage the connector's ease of processing.

The shell is the connector's exterior cover. It has a number of uses like:

Protecting the built-in insulating mounting plate and pins from damage
Aligning the plug and socket after mating & un-mating
Securing the connector

The Importance of Electronic Connectors in Communication Applications

The rise of mobile devices has caused connectors to become more widespread. Because of this dependence, their ability to perform well and be reliable is highly important.

In both wired and wireless systems, they are essential for reliable signal transmissions.

Poor quality connectors can cause a number of problems.

Crosstalk between the contact pins of a connector may occur. They can also have the wrong delay time, which can have an impact if a device has timing requirements.

Wireless Communication

In the case of wireless communication, there are some extra considerations to keep in mind.

Effective wireless communication in the workplace requires reliable electrical connections. They must function well no matter the working environment and intensity of work during a service period.

To achieve this, a range of electronic connectors are required, such as:

RF connectors
Power connectors
Backplane connectors
Input and output connectors
Printed circuit board connectors
Wire crimp, insulation displacement (IDC), or solder

Reliable connectors are especially important for standardized interconnections. This allows the equipment of different companies to better connect with each other to meet the needs of a business or community.

There are a number of ways to ensure good wireless connectivity. However, most of them are only done on the manufacturing floor.

One way to do so is to ensure that the external features of the shell are easy to guide with guide pins, especially for insertion. It is also helpful to make sure that power supplies with high-power capacity have their own terminals.

A gold-plated contact can help improve wear resistance. A redundant contact interface, on the other hand, can boost reliability. By using differing pin heights, it helps ensure the order of signal and ground connection.

Performance Considerations of Electronic Connectors

There are three basic categories for how electronic connectors work.

Mechanical performance refers to insertion and extraction force. If the extraction force is too small, it will affect the reliability of a contact pin. The insertion and mechanical life of a connector are affected by the contacts:

Structure
Coating quality
Accuracy of alignment

A connector's electrical performance includes its contact resistance, insulation resistance, and dielectric strength.

Contact resistance measures how resistant contacts are to current flow. It should be low and stable in electronic connectors.

Insulation resistance measures how well the insulation works between contacts and the contacts and shell.

Dielectric strength measures the ability of contacts to withstand the test voltage. Like insulation resistance, it measures between contacts or the contacts and shell.

The environmental performance involves a connector's ability to resist conditions like:

Temperature
Humidity
Salt spray
Vibrations
Shock

There are several ways to protect connectors against this type of damage. This includes proper sealing, liquid immersion, and low air pressure.

Choosing Reliable Electric Connectors

The reliability of your communication system is only as good as your electronic connectors.

At Bead Electronics, we provide custom contact pins to fit the needs of a wide range of applications that work in aerospace and defense, communication, industrial, lighting, medical, automotive, and other industries.

With our unique swaging process, we can ensure consistent quality and precision when designing pins. This allows us to decrease the abrasion of mating surfaces and lower how much force is required for insertion.

Different Connectors and Where they are Used

Where are electrical connectors used?

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