In the world of electrical components, there can be some confusion surrounding terminals and connectors. For some people, a terminal and a connector may seem so similar as to be interchangeable. But in fact, there can be certain differences.
What is a Terminal?
A terminal is an electrical accessory. As the name suggests, it is an endpoint. It acts as the reusable endpoint to a conductor, where you can connect circuits. In this sense, a terminal is a kind of connector.
This accessory is also known as a terminal block. It is made of metal, and it is sealed inside a plastic casing.
It contains holes at both ends, into which you can insert a wire. The general use of a terminal block is for connecting internal and external wiring of printed circuit boards (PCBs) and power terminals.
What is a Connector?
A connector is a device that connects two active devices, to transmit signals or an electric current.
There are two parts to a connector:
- The plug-in, and
- The connector.
Connector is also a general term, also known as a connector assembly, which connects different circuits.
Does the Difference Matter?
In any electrical or electronic application, it’s important to select the right component for the task.
The main thing to note here is that although a terminal or terminal block can be different from a connector, it is also a type of connector in its own right.
This might seem a little confusing, but it makes more sense when you look more closely at the different practical applications of terminals and connectors.
Terminal or Connector?
There are some practical differences in the application of terminals and connectors.
For example, where you have two wires you wish to be able to connect or disconnect when you want, you can use a terminal for this.
Using a terminal block, you can connect or disconnect your wires at any time, with no soldering required.
Connectors come in a wide variety of types, which reflects the broad range of applications they have.
There are rectangular connectors, circular connectors, stepped connectors and many more.
Connectors can also have different properties, depending on the conditions and circumstances in which you use them.
These different features include:
- Locked – held in place with a mechanism that prevents accidental movement or breakage
- Keyed – for connecting only when in the proper orientation, preventing accidental damage from insertion in the wrong socket
- Water-resistant – protection from water damage due to splashes or dampness
- Hermetically-sealed – for complete but safe submersion in water
- ESD shielded – protection from electrostatic discharge
- EMI or RFI filtering – protection from electromagnetic interference (EMI) or radio frequency interference (RFI)
- Oil or moisture-resistant.
How Do You Choose a Terminal or Connector?
Pretty much every electrical installation will require conductors of different parts of a circuit.
To do this some sort of connector, whether it’s a terminal block, a junction box or something similar.
However, deciding what type of connector to use must also take into account safety requirements for electrical connections.
British Standard BS 7671 is the current standard for electrical wiring in the UK.
When selecting your means of connecting wiring, you must consider:
- The material and insulation of the conductor
- How many wires there are, and their shape
- The cross-section area of the conductor
- How many conductors you’re connecting together
- What temperature the terminals will reach during normal service
- Whether you need some form of locking where there could be vibrations or thermal cycling.
Your connectors must also be accessible for inspection, testing and maintenance.
Examples of Terminals and Connectors
Wire to board connectors include mounted, screw-based or screwless terminal blocks and connectors.
Screwless connectors are ideal for use with test and measurement equipment, robotics, energy metering, building automation and electrical devices.
PCB connectors join sections of circuits together on PCBs.
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