What is a terminal? Difference between electrical connector and terminal or terminal connector
In the context of electronics and electricity, the terms "connector" and "terminal" refer to components that facilitate electrical connection between devices or components. Although they are often used interchangeably, there is a subtle distinction between them:
- Connector: A connector is a device designed to join two or more parts of an electrical circuit, allowing repeated connection and disconnection. Connectors can be pluggable or non-pluggable. Common examples of connectors are plugs and sockets, coaxial connectors, USB connectors, HDMI connectors, etc. Connectors provide a form of mechanical connection as well as an electrical interface between two devices or cables.
Terminal: A terminal is the connection point where an electrical conductor is attached to an electrical device or component. Terminals provide a solid and reliable connection point for an electrical conductor to connect to a component or device. Terminals can come in various shapes and styles, such as hollow tips, faston terminals, spuds, etc. Its main function is to provide a solid and safe electrical connection point between a wire and another circuit component.
In short, while a connector is a device that facilitates repeated connection and disconnection between two parts of an electrical circuit, a terminal is the specific connection point where an electrical conductor is attached to a component or device. Connectors may contain terminals, but not all terminals are necessarily associated with a pluggable connector.
Types of terminal connectors
As we have said before, in some cases the terminals are part of a connector, but other times they act individually to make a connection between a cable and another element, but not with the idea of regularly connecting and disconnecting both parts.
In this section we will refer precisely to this type of terminals that are not part of connectors and are used individually. Due to the type of insulation, these terminals can be insulated or bare. The isolation can be partial or complete of the entire terminal. All terminals that have insulation are known as pre-insulated terminals.
Material used in pre-insulated terminals: There are fundamentally two types of materials used in pre-insulated terminals, although they do not have to be the only ones.
- Nylon: It is a strong and durable thermoplastic material that is commonly used in pre-insulated terminals. Nylon provides good resistance to abrasion, heat and chemicals, making it suitable for a wide range of electrical applications.
- PVC (Polyvinyl Chloride): PVC is another thermoplastic material widely used in the manufacture of pre-insulated terminals. It is known for its flexibility, heat resistance and electrical insulation. PVC is also resistant to most chemicals, making it suitable for industrial and commercial environments.
In general, there are three main sizes, each identified by a different color, for the insulated terminals commonly called pre-insulated. These three sizes are each identified by a standard color:
| |
Terminal color |
Cable section |
| |
Red |
Used for small gauge wires such as AWG 22-18 (0.50 mm² to 1.00 mm²) |
| |
Blue |
Used for medium gauge cables such as AWG 16-14 (1.50 mm² to 2.50 mm²) |
| |
Yellow |
Used for larger gauge cables, such as AWG 12-10 (4.00 mm² to 6.00 mm²) |
Esta designação de cor não é seguida nas biqueiras ocas, como veremos a seguir.
Os terminais pré-isolados são conectados ao cabo por meio de umPre-Insulated Terminal Crimping Pliers. É facilmente identificado porque todos possuem três furos com três pontas vermelhas, azuis e amarelas.
Devido ao formato do terminal, estes são principalmente os que discutiremos abaixo:
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Hollow toe caps:
A socket ferrule is a type of terminal used in electrical and electronic applications to connect wires to devices or components. These ferrules have an open or hollow end that allows the conductor cable to be inserted inside.
Hollow ferrules are commonly used in applications where a safe and reliable connection between a cable and a terminal is required, such as in electrical control panels, distribution panels, electronic equipment, among others. They provide a firm and stable connection, helping to prevent accidental separation of the cable from the terminal.
These ferrules can come in different sizes and configurations to accommodate various types of cables and terminals. Its hollow design allows the lead wire to be easily inserted into the terminal, and then held in place by crimping, thus providing a solid and long-lasting electrical connection.
There are several color assignments depending on the size of the hollow toe, but the most common or widespread is the one shown below:
| |
Color |
Lead wire section |
| |
Violet |
0.25 mm² |
| |
White |
0.50 mm² |
| |
Bue |
0.75 mm² |
| |
Red |
1.00 mm² |
| |
Black |
1.50 mm² |
| |
Gray |
2.50 mm² |
| |
Orange |
4.00 mm² |
| |
Green |
6.00 mm² |
| |
Brown |
10.0 mm² |
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Solid ferrules:
A solid ferrule is a type of terminal used in electrical and electronic applications to connect cables to devices or components. Unlike hollow toes which have an open or hollow end, solid toes have a solid end.
These ferrules are usually made of a conductive material, such as copper, and are designed to be crimped or soldered to a conductive wire. After connection, the solid end of the ferrule is inserted into a suitable terminal or connector to establish the electrical connection.
Solid dropouts provide a sturdy, long-lasting connection as the solid end offers a larger, more stable contact surface. This helps ensure low electrical resistance and a secure connection, which is important in applications where signal reliability and integrity are critical.
These ferrules can come in different sizes and configurations to accommodate various types of cables and terminals, and are used in a wide range of applications, such as electronic equipment, control panels, wiring systems, among others.
Basically there are two forms:
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Solid cylindrical toe
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Solid flat toe
In both cases, the solid ferrules are manufactured pre-insulated with the three colors that we saw previously (red, blue and yellow) and bare for even larger sections of cables.
A round terminal is a type of connector or terminal used in electrical and electronic applications to facilitate the connection of electrical cables. As its name indicates, this type of terminal has a circular or rounded shape at its end.
Round terminals are designed to be used in conjunction with other components, such as terminal blocks or connectors, which also have a circular or cylindrical shape. Inside they have a circular hole through which the screw that makes the connection passes through. These terminals can be used in a variety of applications, from home wiring systems to more demanding industrial applications.
Round terminals are often manufactured in different sizes to accommodate various wire gauges and specific applications. They can be made from different conductive materials, such as copper or copper alloys, to provide a safe and reliable electrical connection.
As with the solid toe caps, there are pre-insulated ones (red, blue and yellow) and bare ones.
A fork terminal is a specific type of terminal connector used in electrical and electronic applications. Its name comes from its characteristic shape, which resembles a fork or fork. This type of terminal has two curved U-shaped arms on one end that allow it to hook around a screw, bolt, or connecting post.
Fork terminals are commonly used in applications where a secure and reliable connection to a terminal or connecting post is needed, such as in electrical distribution panels, electronic equipment, and wiring systems. They allow a firm and stable connection around the screw or bolt, helping to ensure good electrical conductivity and a solid connection. Although the application of a round terminal and a fork terminal is similar, in round terminals you have to remove the screw completely to extract the terminal, in fork terminals you only need to loosen the screw.
These terminals are available in a variety of sizes to accommodate different wire gauges and specific applications. They can also be made from different conductive materials, such as copper or copper alloys, to provide a high-quality electrical connection.
As with other types of terminals, there are bare and pre-insulated fork terminals in the three colors that we have already seen.
A faston terminal is a specific type of electrical connector used to connect wires to electrical devices or components quickly and securely. It is also known as a quick connect or quick disconnect terminal.
Faston terminals are used individually like the rest of the terminals, but they are also used in contact blocks where a certain number of this type of terminals are inserted to finally form a connector. We call this type of receptacles a faston holder. They are also used to connect other components with the cable, such as switches, fuse holders, network sockets, speakers, etc.
One of the main advantages of Faston terminals is their ease of connection and disconnection. This allows for quick and efficient installation and maintenance, which is especially useful in environments where frequent changes or repairs are required. Additionally, they provide a safe and reliable electrical connection when properly installed.
Faston terminals come in a variety of sizes and configurations to accommodate different wire gauges and specific applications. They are designed to provide a strong and durable connection, thus contributing to the reliability and safety of the electrical system in which they are used.
And like other models, there are versions with bare faston terminals and pre-insulated ones.
The four existing faston terminal sizes are: 2.8mm, 4.8mm, 6.3mm and 9.5mm
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Cylindrical or bullet terminals
Barrel terminals or bullet terminals are a type of electrical connector used to connect wires to electrical devices or components. These terminals receive their name due to their cylindrical or bullet shape at one end.
Bullet terminals are made up of two parts: the male terminal and the female terminal. The male terminal has a cylindrical or bullet tip on one end, while the female terminal has a cavity of the same diameter that allows the male terminal to be inserted.
This type of connector is commonly used in applications where a quick and secure connection is needed, such as in automotive, motorcycle, electronic equipment, and home appliance wiring systems. Bullet terminals make it easy to quickly connect and disconnect cables without the need for special tools.
Barrel or bullet terminals come in different sizes and diameters to accommodate a variety of wire gauges and specific applications. They provide a reliable electrical connection and can be used in a wide range of environments and applications.
In this type of terminal we can also find naked models and pre-insulated ones in the three sizes already mentioned.
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Sprats
There are flat and solid ones. They are used to connect a cable with the contacts of a printed circuit, in a simpler or more economical way than using a terminal block connector.
In practice, the user can directly solder the cable to the blade or use a female terminal compatible with said blade and connect the cable to the PCB.
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Other types of connection terminals: Splices and taps, often called current stealers, are another type of widely used terminal.
