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PCB Connector Types – What You Need To Know

Electrical and electronic devices are getting smaller and more powerful as technology evolves. Consequently, there’s a need for smaller, highly efficient, and more robust interfaces between close components. One such type of interface is the printed circuit board connectors.  With time we’ve had a lot of PCB connector types. Therefore, finding the best ones for your project can be pretty challenging. 

Here, we’ve got the information and tools necessary to ensure that you complete your project in time. But first, read on to find out the different types of PCB connectors.

Board to Board Connectors

A Printed Circuit Board

Fig 1: A Printed Circuit Board

From the name, board-to-board connectors link two printed circuit boards without a cable. They provide reliable connections and best-in-class signal, and mechanical integrity. Consequently, they excel and are prevalent in high-speed, high-power, high-density, and micro-miniature applications.

If designing a system with a permanent PCB layout, you can hard solder the board to board connectors.

Here, let’s take a quick look at the various types of board-to-board connectors.

Terminal Blocks

They’re a group of connectors that allow easier interfacing between two boards without physically connecting mechanical parts. You can identify terminal blocks in PCBs where one piece attaches to the board, and the other end has wires. These wires allow for easy swapping between the boards. 

An example is a 2-pin connector.

2-pin PCB connector

We use the 2-pin PCB connectors to connect wires to boards. For example, connecting a peripheral device such as a sensor or motor to a committee.

Posts

Posts resemble terminal blocks, attaching wires to a board without joining the parts. They’re common in audio devices and electronic test equipment.

Plug and Sockets

Simply put, PCB connector plug and socket connectors have male and female links made up of a set of pins. They’re the most popular connector types that you can use to transmit display, power, or even data signals. For example, a USB is a plug-and-socket connector.

Wire to PCB Connector

Wire to PCB connectors connect a wire to a PCB and have high reliability and flexibility.

Flexible PCB Connector

Flexible PCB connector

Fig 2: Flexible PCB connector

Flexible PCB connectors are designed for applications requiring a compact design. Other applications include those that demand pitch spacing, smaller centerlines, lighter interconnections, and lower profile heights.

USB Connectors

USB connectors

Fig 3: USB connectors

Universal Serial Bus (USB) connectors are the modern-day standard interfaces for consumer electronic devices and personal computers. They were developed to overcome the shortcomings of their predecessors (FireWire and RS-232 parallel and serial). 

For more about USB connectors, check here.

RCA Connectors

RCA connectors

Fig 4: RCA connectors

Source: Wikipedia

Before we had HDMIs, we had the RCA connectors. They’re electrical connectors we use to carry audio and video signals. Often, you can quickly identify them by their red, white, and yellow heads on RCA plugs (male) and jacks (female). They’re found in older amplifiers, home theatre systems, and mixers.

Audio Connectors

You can quickly identify an audio connector unless you’ve never used headphones or earphones. They’re the ones used to transmit analog audio signals between devices.

Here, let’s look at their various types.

¼” (6.35mm)

The 6.5mm audio connector is pretty old, and you’ll find most in audio equipment, including DVD players and amplifiers.

⅛” (3.5mm)

You’ll find the 3.5mm connectors in headphone applications that plug into laptops, MP3 players, and smartphones. Additionally, they come in the same size but may have different numbers of wires. For instance, you’ll get either 3 or 4 wires.

In most cases, you’ll find headphones with stereo sound. A 3-wire audio connector usually transmits mono sound. On the other hand, a 4-wire audio connector transmits full stereo sound.

2.5mm

The 2.5mm audio connector uses a tip-ring-ring-sleeve (TRRS) to have both microphone and headphones on the same jack.

Power Connectors

From the name, power connectors transmit power to the PCB. Here, we’ve three categories: heavy-duty, medium-duty, and light-duty connectors.

A heavy-duty connector carries more current than a light-duty one.

Barrel Connectors

DC barrel connectors

Fig 5: DC barrel connectors

Barrel connectors transmit power to the PCB and are famous for their versatility and adaptability. They’re inexpensive and can adapt to various power ratings and voltages.

Additionally, when buying a barrel connector, look out for the following:

The Sleeve

Different connectors come with different outer sleeve diameters. Specifically, the sleeve can either be 3.5 or 5.5mm in size.

The Pin

It is the metallic part of the connector. The pin’s size depends on the size of the sleeve. For example, a 5.5mm sleeve matches a 2.34 mm pin diameter. 

The Polarity

The polarity determines whether the sleeve voltage is lower or higher than the pin voltage.

Molex Connectors

Molex connectors are bulkier than barrel connectors and best suited for optical and power hard drives. They have a high current capacity with a single pin rating of up to 11 amperes.

IEC Connectors

IEC connectors transmit alternating current (AC) power to your device. You can find them with older TVs and computers with internal power units that convert the energy to DC power. In most cases, IEC connectors are employed in electrical appliances as power couplers.

Pin Header Connectors

If you’ve had a PCB prototype, you’re familiar with the pin header connectors. The connector is a bridge between isolated and blocked circuits within a circuit. Therefore, it helps with transmitting either signals or currents.

You’ll always find one side with PCB-soldered pins that stick up to receive a female socket connection. Additionally, the pins are held together by a plastic structure that snaps apart as needed.

JST Connectors

The Japan Solderless Terminal (JST) is a design standard representing a wide range of wire-to-board connectors. These connectors adhere to the standards of the JST Mfg. Co. Furthermore, you’ll find these connectors in radio-controlled servos, battery balancers, rechargeable battery packs, and 3D printers.

Prototyping & Testing Connectors

Prototyping and testing can be full of mistakes and errors; hence you wouldn’t want to use some of the permanent connections we’ve addressed above. As a result, you can use one of the quick connectors such as:

Banana Connectors

Banana connectors, otherwise known as banana plugs, involve a single conductor employed to link wires to equipment. They’re designed with a male banana plug and a female banana jack.

Alligator Clips

Alligator Clips

Fig 6: Alligator Clips

Alligator clips are mainly used to link a wire to either a cathode or anode of a device. Also, you can use them to connect two wires. In most cases, they’re found in laboratories, especially with batteries.

IC Clips

If you need a connector with a blend of rigidity and finesse, the IC clip suits you perfectly. You can attach them to integrated circuit (IC) pins without fear of contacting other pins. Consequently, they fit troubleshooting applications.

Conclusion

As technology evolves and we develop more sophisticated devices, the need for better power and signal transmission channels arises. 

Luckily, we’ve got all the essential information on PCB connectors in today’s article. Finally, contact us if there are some grey areas within the article or if you need help with your project.

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Hommer Zhao
Hi, I am Hommer, the founder of WellPCB. So far, we have more than 4,000 customers worldwide. If you have any questions, you can feel free to contact me. I really appreciate any help you can provide.

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