Classification and Main Applications of Connectors

As key components for realizing circuit, signal, or energy transmission and connection, connectors are widely used in electronics, machinery, communications, and various other fields. They can be categorized by application scenarios, transmission media, structural forms, etc., with each type playing an irreplaceable role in specific domains. The following details the characteristics and uses of each connector type based on core classification dimensions.

I. Classification and Applications by Field

1. Industrial Connectors

• Features: High reliability, vibration resistance, and tolerance to high/low temperatures, often with sealed designs for harsh industrial environments.
• Main Applications:

◦ Automation Equipment: Used for connecting PLC (Programmable Logic Controllers), sensors, and actuators. For example, M12 circular connectors ensure stable signal transmission in industrial production lines.

◦ Power Systems: High-voltage connectors are applied in power substations and distribution cabinets. wall-through connectors isolate high-voltage circuits to ensure operational safety.

◦ Mechanical Manufacturing: Rectangular industrial connectors (e.g., HARTING Han series) are commonly used in modular interfaces of machine tools and robots, supporting quick plugging/unplugging and maintenance.

2. Automotive Connectors

• Features: Require high temperature resistance, electromagnetic interference (EMI) protection, and water/dust proofing (IP67/IP68 ratings); some types support high-current transmission.
• Main Applications:

◦ Power Systems: High-voltage connectors for new energy vehicles (e.g., TE’s HVP series) connect batteries, motors, and electronic control systems, carrying hundreds of amperes of current.

◦ In-vehicle Electronics: Automotive USB and HDMI connectors support data transmission for in-car entertainment systems and rear-view cameras; CAN bus connectors enable in-vehicle network communication.

◦ Safety Systems: Connectors for airbags and ABS braking systems must have high response speed to ensure real-time signal transmission in emergencies.

3. Communication and Data Transmission Connectors

• Features: Focus on high speed, low latency, and anti-interference capabilities, covering electrical and optical connectors.
• Main Applications:

◦ Network Equipment: RJ45 connectors (Ethernet ports) are core components of Ethernet communication; optical fiber connectors (e.g., LC, SC types) are used for high-speed optical signal transmission in data centers, supporting 10G/100G networks.

◦ Mobile Communications: RF connectors (e.g., N-type, SMA-type) in 5G base stations connect antennas to RF modules, ensuring signal transmission efficiency.

◦ Consumer Electronics: USB-C and Thunderbolt connectors enable high-speed data transmission and charging for phones and computers, while HDMI interfaces support 4K/8K video output.

4. Consumer Electronics Connectors

• Features: Pursue miniaturization, low power consumption, and multi-functional integration, often using board-to-board or wire-to-board connection methods.
• Main Applications:

◦ Smartphones: Lightning and USB-C interfaces are used for charging and data transmission; SIM card connectors and camera connectors integrate functional modules.

◦ Wearable Devices: Magnetic connectors (e.g., Apple Watch charging ports) have become mainstream due to their convenience, and flexible printed circuit (FPC) connectors link screens to motherboards.

◦ Home Appliances: Control board connectors for refrigerators and air conditioners support sensor signal transmission; wireless charging connectors (e.g., Qi standard) enable contactless energy transfer.

II. Classification and Applications by Transmission Medium

1. Electrical Connectors

• Features: Transmit current or electrical signals, the most widely used connector type, divided into low-frequency and high-frequency categories.
• Main Applications:

◦ Low-frequency Electrical Connectors: D-sub (DB) connectors for printers and serial devices; terminal block connectors for electrical wiring in distribution cabinets.

◦ High-frequency Electrical Connectors: SMP and SSMA connectors are used in microwave communications and radar equipment, supporting signal transmission in GHz frequency bands with minimal attenuation.

2. Optical Connectors

• Features: Use optical signals as carriers, offering high bandwidth and EMI resistance, requiring matching with optical fibers.
• Main Applications:

◦ Communication Networks: SC/APC connectors in fiber to the home (FTTH) connect incoming optical fibers to optical modems; MPO/MTP connectors in data centers support high-density fiber arrays for multi-gigabit bandwidth transmission.

◦ Medical Equipment: Optical connectors are used in laser surgical devices and endoscope light source transmission, ensuring stable optical signals without EMI.

3. Fluid Connectors

• Features: Transmit liquids or gases, often with quick-connect designs and leak-proof functions.
• Main Applications:

◦ Cooling Systems: Fluid connectors in server liquid cooling solutions circulate coolant, connecting cold plates to pipelines; fuel connectors in automobile engines ensure fuel supply.

◦ Medical Field: Fluid connectors for infusion sets and ventilators must meet biocompatibility standards to ensure safe and sterile liquid/gas transmission.

III. Classification and Applications by Structural Form and Connection Method

1. Circular Connectors

• Features: Circular interface, often using threaded or bayonet connections, with good sealing and vibration resistance.
• Main Applications:

◦ Aerospace: MIL-DTL-38999 series circular connectors are used in aircraft avionics and missile guidance systems, meeting reliability requirements in harsh environments.

◦ Industrial Automation: M8/M12 circular connectors connect waterproof sensors and encoders, common in wet or dusty industrial scenarios.

2. Rectangular Connectors

• Features: Compact structure, accommodating more pins, often using plug-in or latch connections.
• Main Applications:

◦ Computer Motherboards: PCIe and SATA connectors link motherboards to graphics cards and hard drives, supporting high-speed data transmission.

◦ Medical Devices: Rectangular connectors serve as signal interfaces for CT and MRI equipment, such as D-sub 50-pin connectors for image data transmission.

3. Bar Connectors

• Features: Pins arranged in a straight line, mainly for board-to-board or wire-to-board connections, with a small footprint.
• Main Applications:

◦ Consumer Electronics Motherboards: FPC/FFC connectors link flexible circuit boards to motherboards, commonly used in smartphone screens and camera modules.

◦ Smart Home Devices: Bar connectors enable internal circuit connections in smart sockets and sensors, supporting modular design.

IV. Special-purpose Connectors for Specific Fields

1. Military Connectors

• Features: Meet strict standards like MIL-SPEC, with impact resistance, extreme temperature tolerance, and salt spray protection.
• Applications: Used in weapon systems and communication equipment of tanks and fighter jets, such as MIL-C-5015 series connectors ensuring tactical communication stability.

1. Medical Connectors

• Features: Require biocompatibility certification (e.g., ISO 10993), support sterilization, and some have anti-misplug designs.
• Applications: Connectors for ECG monitors and in vitro diagnostic devices, such as medical-grade USB interfaces ensuring safe data transmission and device power supply.

V. Development Trends of Connectors

With the advancement of 5G, IoT, and new energy technologies, connectors are evolving toward miniaturization, high speed, and integration. For example, high-speed backplane connectors support data transmission over 112Gbps, and the integrated application of liquid cooling and optical connectors has become a key solution for data center heat dissipation. In the future, connectors will play a more central role in intelligent and green scenarios, driving technological upgrades across industries.

Conclusion

The classification system of connectors is closely tied to application scenarios. From industrial equipment to consumer electronics, and from electrical to optical/fluid transmission, each type aims to achieve “reliable connection”. Understanding their classification and applications helps accurately select suitable connectors in design and manufacturing, ensuring stable and optimized system performance.