Views: 69 Author: Site Editor Publish Time: 2022-07-20 Origin: Site
PCB terminal blocks are modular insulated devices that are mounted on printed circuit boards (PCBs) to hold two or more wires together. A PCB spring terminal block is used to secure or terminate wires and, in its simplest form, comprises several separate terminals in a long array. Terminals can be used to connect wires to ground or to connect electrical switches and outlets to a power source.
The terminal body usually constitutes a copper alloy with the same coefficient of expansion as the wire to be used. This not only prevents loosening due to the difference in expansion rate, but also reduces corrosion caused by the electrolytic action between the two different metals.
PCB terminal blocks can be classified based on structure and device types.
Single feed products stand for the basic type of terminal block, used for wire-to-wire connections. Single feed terminal strips have one input and one output contact: two different wires are fed into either side of the terminal strip and connected within its housing.
Double-level PCB terminal blocks have two contact levels; this arrangement saves space and eases wiring. Multi-level products can be bridged to connect one contact level to another for added circuit flexibility.
Terminal blocks can also be classified according to the application or the type of device to which they are connected.
Grounding circuit terminals--They are used for grounding components or systems, and are usually exchangeable with standard terminal blocks and can be inserted into the terminal block as required.
Fuseholders--They connect a couple of fuses related to many devices. In the event of a short circuit, only the portion of the line connected to the fuse block is affected.
Thermocouple block--It is used to connect thermocouples and provides a consistent metal connection for temperature measurement.
The I/O block--It provides communication between the device and the controller.
The power distribution block-- It is used to terminate power lines.
Disconnect blocks-- They allow easy disconnection of circuits using knife switches without removing wires.
When selecting a PCB terminal block, it is essential to do some research on the important terminal block specifications, which can help you end up buying high-quality and suitable products.
The term " contact ", also referred to as position, way or pole, is the wire that is connected to the terminal block. The number of contacts is an important specification when selecting a PCB terminal block, as the customer needs to match this number to the number of wires required for the project or application.
Contact pitch refers to the distance between each contact, measured from the centre of each hole or opening. Contact pitch is directly related to the number of contacts and is usually expressed in millimetres (mm). Common options include 2.5 mm terminal blocks, 3.5 mm terminal blocks, 3.81 mm terminal blocks, 5.08 mm terminal blocks, etc.
Terminal blocks are usually manufactured to receive a range of wire or conductor sizes. Wire sizes in North America are expressed in American Wire Gauge (AWG), which is the standard for non-ferrous wire conductor sizes. A higher AWG number represents a smaller conductor diameter and vice versa. For instance, a typical AWG 12 household wire has a larger diameter than AWG 22 telephone wire.
Terminal blocks allow for a few different methods to make wire connections.
Screw clips use screws to tighten the wire and create an electrical connection - the classic, industry-standard method of termination. This type can fit a very broad range of wire sizes and offers a reliable connection.
Spring clamps use the power of a spring to keep the wire clamped. They represent a more recent alternative to screw clamps and are particularly useful in applications using small wire diameters and limited workspace.
Insulation displacement connections (IDC) slide the wire between two pieces of sharp metal, allowing connections to be made without revealing any bare wire.
Tabbed connections are designed to be inserted and removed quickly without soldering. They are also referred to as spade or blade terminals.
You should now have a deeper understanding of the types of PCB terminal blocks and how to select them. If you have any questions about PCB terminal blocks, you can always contact us and our experts will be there to give you professional answers.