Connector Types and Selection Guide

A connector is a device used to connect two or more electrical circuits. As an electromechanical component, connectors are usually used in pairs, consisting of a plug (male end) and a receptacle (female end). The plug is often referred to as a plug, male connector, or header, while the receptacle is called a socket, jack, or female connector.

Connectors facilitate electrical connection and disconnection through mechanical action. Their primary functions include:

• Transmitting signals or power
• Connecting or disconnecting circuits

Types of Connectors

Connectors come in many different types, designed to meet various needs. Here, we’ll focus on connectors that carry electrical signals. There are contact-based connectors (such as electrical and fiber-optic connectors) and non-contact connectors (e.g., proximity switches). In this article, we'll primarily cover contact-based electrical signal connectors.

Electrical connectors and their components are critical interface elements within devices, enabling signal and power transmission across systems. The quality of the connection directly impacts the safety and reliable performance of the entire system.

From high-frequency to low-frequency connectors, from circular to rectangular, from connectors carrying large currents to those transmitting weak signals, connectors are integral to numerous systems. They ensure devices operate at their full potential, supporting a wide range of functionalities.

Given the diversity of applications, industrial connectors are categorized in a variety of ways. With ongoing technological advancements, the performance and material choices for connectors are constantly improving to ensure reliable operation in different environments.

Connector Classification

Connector classification can be quite complex, and many systems use specific types tailored to their environments and requirements. Here are the most common ways connectors are categorized:

By Application Layer (Connection Function)

• A: Component-to-package connection
• B: Package-to-PCB (Printed Circuit Board) connection
• C: Board-to-board connection
• D: Component-to-component connection
• E: Component-to-I/O interface connection
• F: System-to-system connection

By Signal Type

• A: Power connectors (for transmitting power)
• B: Signal connectors (for transmitting signals)
• C: High-frequency connectors (for transmitting data)

By Electrical Requirements

• A: General-purpose connectors
• B: High-power connectors
• C: High-voltage connectors
• D: Pulse connectors
• E: Low-noise connectors
• F: Phase-matching connectors
• G: Precision coaxial connectors

By Operating Frequency

High-frequency connectors, coaxial connectors, video connectors, impedance converters, and more. These connectors are designed to handle different frequencies and signal types.

By Environmental Conditions

• A: Sealed connectors
• B: High-water-pressure sealed connectors
• C: High-vacuum sealed connectors
• D: Tri-proof connectors (e.g., water, dust, corrosion resistant)
• E: Radiation-resistant connectors
• F: High-temperature connectors
• G: Low-temperature connectors

By Physical Shape

• Circular connectors: Often used in military and aerospace applications, available in various locking mechanisms such as quick-lock, screw, and push-pull designs.
• Rectangular connectors: Commonly used for PCB connections and available in various mounting and locking configurations.

By Application Field

• A: RF (Radio Frequency) connectors
• B: Fiber-optic connectors
• C: Non-contact connectors (e.g., proximity sensors)

Key Principles for Connector Selection

When selecting a connector, several factors should be considered to ensure proper performance:

Current Rating

Choose connectors that can handle the required current without overheating or damaging the electrical components. For power connectors, ensure proper current ratings and insulation.

Size and Structure

The physical dimensions of the connector are crucial, especially in confined spaces. Make sure to choose connectors that fit into your device or circuit board without interference. Options include front or rear mounting, fixed or quick-lock mechanisms.

Impedance Matching

For RF signals, impedance matching is critical. Mismatched impedance can cause signal reflection and loss. Choose connectors that meet the impedance requirements for high-frequency applications.

Shielding

With the rise of wireless communication and electromagnetic compatibility (EMC) concerns, shielding is more important than ever. Choose connectors with metal housing or molded shielding to protect signals from external interference.

Anti-Mating Features

To prevent misconnection, look for connectors with unique designs that prevent incorrect mating. For example, using different types of plugs and receptacles for different circuits can prevent accidents.

Reliability

Since connectors are essential for signal transmission, reliability is crucial. Ensure the connectors have high contact quality and are durable under mechanical stress (e.g., board-to-board connections or pin connectors).

Universal Compatibility

Where possible, choose connectors with standard configurations that are widely compatible, reducing parts variety, lowering costs, and minimizing the risk of supply chain disruptions.

Environmental Suitability

Select connectors based on the operating environment. Connectors for outdoor or industrial applications must be rated for harsh conditions, such as extreme temperatures, moisture, or corrosive environments.

Insertion and Withdrawal Durability

Some applications require frequent plugging and unplugging. Choose connectors rated for high cycles of insertion and withdrawal to ensure long-term performance.

Live or Non-Live Connection

Consider whether the connector will be used in live circuits. In cases where live connections are required, special attention must be given to connector type and safety standards.

Conclusion

Selecting the right connector is crucial to ensuring the reliable performance of your electronic system. Each application has specific requirements regarding current, frequency, size, environment, and durability. By considering these factors, you can choose the most suitable connector that guarantees optimal performance and longevity for your device or system.