Introduction to Common Types of Connectors

(1) Terminal Blocks

Terminal blocks are primarily designed to facilitate wire connections. In essence, a terminal block is a metal piece enclosed within insulating plastic. Both ends of the metal piece feature holes for wire insertion, along with screws for tightening or loosening the connection. In situations where wires need to be connected or disconnected periodically, terminal blocks offer a quick and convenient solution, allowing for disconnection at any time without the need for soldering or twisting wires together. There are many types of terminal blocks; commonly used varieties include plug-in terminal blocks, PCB terminal blocks, screw-type terminal blocks, and barrier terminal blocks.

Features of Terminal Blocks: Diverse pin pitches and flexible wiring methods, suitable for high-density wiring requirements; maximum current capacity of up to 520A; compatible with SMT (Surface Mount Technology) manufacturing processes; suitable for reflow soldering with a maximum temperature resistance of 300°C; functional expansion is possible through various accessories.

(2) Audio/Video Connectors

① 2-pole and 3-pole Plugs and Jacks: Mainly used for signal transmission between various devices, with input plugs often used for microphone signals. 2-pole plugs and jacks are primarily used for mono signal connections, while 3-pole plugs and jacks are mainly used for stereo signal connections. They are categorized by diameter into three standard sizes: 2.5mm, 3.5mm, and 6.5mm.

② RCA Plugs and Jacks: Mainly used in audio and video equipment as input and output connectors for the cables between them.

③ XLR Connectors: Primarily used for connecting microphones to power amplifiers.

④ 5-pin DIN Connectors: Mainly used for connecting cassette tape decks to power amplifiers. They can centralize both stereo input and output signals into a single socket.

⑤ RCA Plugs: RCA plugs are primarily used for signal transmission.

(3) Rectangular Connectors

Rectangular connectors consist of varying numbers of contact pairs housed within a rectangular plastic shell that possesses good insulating properties. The number of contact pairs in these plugs and sockets varies, reaching up to several dozen. They are arranged in two, three, or four rows, etc. Due to the elastic deformation of each contact pair, the resulting normal force and friction ensure a reliable connection. To enhance performance, some contacts are plated with gold or silver.

Rectangular connectors can be classified into pin-type and double-cantilever spring types; with or without an enclosure; and locking or non-locking types. These connectors are commonly used in low-frequency, low-voltage circuits, as well as mixed high/low-frequency circuits, and are predominantly found in radio instruments and metering equipment.

(4) Circular Connectors

Circular connectors mainly fall into two types: push-pull (plug-in) and threaded (screw-coupling). The push-pull type is typically used in circuit connections that require frequent mating and demating, have few contact points, and carry currents of less than 1A. The threaded type is commonly known as an aviation connector. Featuring a standard rotary locking mechanism, it is convenient to connect even with numerous contact points and high mating forces, and it offers excellent vibration resistance. It also easily meets special requirements such as waterproof sealing and electric field shielding, making it suitable for high-current circuit connections that do not require frequent mating. The number of contacts for this type of connector ranges from 2 to nearly 100, with rated currents spanning from 1 to several hundred amperes, and operating voltages between 300 and 500 volts.

(5) PCB Connectors

Printed Circuit Board (PCB) connectors evolved from rectangular connectors and technically belong to this category, but they are generally listed separately as a distinct type of connector. The number of contacts ranges from one to several dozen. They can be used with pin headers or directly mounted onto circuit boards, and are widely used for connecting various daughter cards to the main motherboard in computer hosts. To ensure a reliable connection, the contacts are typically gold-plated to enhance durability; these are commonly known as "gold fingers."

(6) Other Connectors

Other types of connectors include IC (Integrated Circuit) sockets, power plugs and receptacles, fiber optic connectors, and ribbon cable connectors.