Sep 11, 2019|General
PCB connectors come in a range of types, styles, configurations, and looks. Here’s everything you need to know about PCB connectors—including what to use and when.
What are PCB Connectors?
Table of Contents
- 1 What are PCB Connectors?
- 2 PCB Connector Types
- 2.1 Terminal Blocks
- 2.2 Posts
- 2.3 Plug & Sockets
- 2.4 Card Edge Connectors
- 2.5 Backplane Connectors
- 2.6 Board to Board Connectors
- 2.7 USB Connectors
- 2.8 RCA Connectors
- 2.9 Audio Connectors
- 2.10 Power Connectors
- 2.11 Pin Header Connectors
- 2.12 JST Connectors
- 2.13 RF Connector Conventions
- 2.14 SMA Connectors
- 2.15 RP-SMA Connectors
- 2.16 Prototyping & Testing Connectors
PCB connectors are printed circuit boards, and they exist in nearly every type of technology today. A PCB connector is usually a green square with visible connections, grooves, and lines. PCB manufacturers make the devices in single- or double-sided configurations with multiple layers.
PCBs have traces of varying thickness, with thicker traces providing avenues for higher currents to travel. A trace width calculator can determine the trace width for PCB conductors. Trace width is a crucial measure which dictates how much current can pass through the board.
PCB Connector Types
Because so many types—and sizes—of electronics use PCB connectors, there are tons of variations available.
Terminal block connectors involve a housing—the terminal block—plus wiring which removes easily. An excellent temporary way to connect parts, terminal block connectors are easy to swap out.
Post connectors are another quick-connect solution. These are common in audio applications and test equipment. Posts use clamps and screws for attachment, and they’re straightforward to remove and re-connect.
Plug & Sockets
Plugs and sockets are the most common type of connector. As their name suggests, plug and socket connectors feature male and female “parts” which connect in a single orientation. Plug and socket connectors apply to various connection scenarios for everything from power supplies to data transmission.
Card Edge Connectors
PCB edge connector pieces help adhere expansion slots to printed circuit boards.
Backplane connectors are a unique type of PCB that connects with other PCBs. It’s like a computer’s motherboard and contains the connections for expansion boards.
Board to Board Connectors
Board to board connectors connect two PCBs via pins and receptacles.
Most consumers today are familiar with USB connectors. We use them for our smartphones, tablets, smartwatches, keyboards, computer mice, and more. All USB connectors have at least four contact points. Two transmit and receive data, one serves as the ground, and one receives power.
Type A USB connectors are standard on laptops and computers. The “female” end is the receptacle on your device while the “male” end comes in your accessories.
B-type USB connectors are somewhat dated these days, but they’re standard with many electronic devices such as music players.
If you have a newer tablet, phone, or E-reader, you likely have experience with Micro USB connectors. Micro connectors feature male and female connection points.
USB C is the newest type of USB connector and has a few perks. It can handle power, data, and video all at the same time—making it a highly desirable mode of PCB connection. C type USBs also lack polarity, so no flipping and flopping when connecting with these.
RCA connectors are the old-school version of USB. Pre-2000, RCA plugs were the go-to for all types of devices. These hardy connectors transmit stereo audio, composite video, component video, and S/PDIF audio. Of course, in today’s world, it might be challenging to find a device that’s still compatible.
Audio connectors are the type of plug we see with headphones and speakers. With the advent of Bluetooth technology, however, fewer audio connectors exist—especially in newer iPhone versions.
Audio connectors with ¼” plugs are common with music equipment like amplifiers and electric guitars.
Headphones typically feature 1/8” plugs for compatibility with your phone, music player, or computer.
The rarer 2.5mm audio connection option combines microphone and headphone functionality in a dual plug.
PCB power connectors transmit power rather than video or data.
Barrel connectivity is decidedly old-school—you can identify a barrel connector thanks to its AC/DC converter box. Of course, their versatility is part of why they’ve remained popular throughout every decade. Variable power adaptability means you can use these connections for different voltages and power ratings.
You can find Molex connectors on your computer (unless it’s a newer laptop), where these pin models power up drives and other devices. A high amount of current can pass through a Molex connector, making them ideal for specific electronics applications.
IEC connectors are a source of direct AC power. Desktop computers and some older electronics use IEC connectors, and the internal power supplies in these devices convert the power from AC to DC.
Pin Header Connectors
While most laptops have phased out pin header connectors, many desktop computers still rely on these connections to transfer power, video, and more. Pins connect individually or separately, but the most common is a single plug with multiple pins.
JST connectors are precisely fitted connectors for near-permanent applications. If you need to remove one, you might need some tools—and a lot of patience. But the tradeoff is a dependable connection that’s practically immovable.
RF Connector Conventions
RF (radio frequency) connectors operate at radio frequencies in ranges of up to multi-megahertz. You may recall using these connectors with coaxial cables for home TV antenna use. These are the types of connectors you needed to achieve TV service back in the day—and they often gave your fingers a workout.
Relatively ancient technology to many, SMA connectors originally came in male and female versions. However, the somewhat delicate design (the center pin on the male connector could become damaged or damage the opposite connector) led to innovations.
RP-SMA introduced reversed polarized SMA connectors and essentially swapped the design of the cable. This way, all the antennas are “female” and people at home couldn’t ruin their expensive electronics systems by trying to mash the wrong type of plug onto their male connector.
Prototyping & Testing Connectors
In testing and prototyping scenarios, it’s often not worth the time or effort to install (or pay for) more permanent connectors. Three main types of connectors help in these casual situations where you only need a temporary—and easy to remove—connection.
Devices like multimeters use banana connectors, which connect to transmit power.
Alligator clips are familiar to most of us—but the ones we’re referencing here are typically smaller scale than the type on your vehicle jumper cables. Alligator clips are excellent for seriously temporary connections—or ones you need to swap frequently. However, you need to be aware of the environment you’re working in and make sure not to touch the metal clips to nearby hardware.
IC Clips are more focused connectors than alligator options. Each clip connects directly to a pin on a circuit, making it easy to narrow down your search for potential problem areas.