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What is a connector? Hirose Electric, a long-established connector manufacturer, answers the simple questions like "What is a connector?” and provides more technical information including important points for mounted products in our Connector Basics You’ll Want to Know Series.

This article is focused on connectors and the connection components. As we have seen, connectors come in a variety of termination types such as board-to-board and cable. Similarly, there are various types of connection materials. In this section, we will describe typical connection components by the following connector types: shielded cable, FPC/FFC, coaxial cable, and optical fiber.

Shielded Connector

A shielded connector is a connector with a metal shell (surrounding part) for noise control. This design is commonly used in interface connectors.

Shielded Cable

Shielded Connector Design

Shielded connectors are connected using shielded cables and metal shields (braided shields). Crimping the metal shell and the shield of the cable together act as a lightning rod that protects the signal by sending excess noise to the ground.


FPC/FFC Connector

Board-to-Board and Wire-to-Board connectors require a plug/receptacle pair, but FPC/FFC connectors require only one connector because they connect with FPC/FFC. FPC/FFC insertion to the connector generally requires three steps: 1. Open the actuator (lid) 2. Insert the FPC/FFCC to the specified position. 3. Close the actuator.


FPC stands for Flexible Printed Circuits. It is made by printing copper traces and circuits on a film, which can be freely shaped and allows connector mounting. Additionally, FPC also have high heat resistance.

FPC Connector


FFC stands for Flexible Flat Cable. FFC consist of several flat conductors laminated with a plastic film. In general the connector design remains the same regardless of whether it is used with FPC or FFC. Unlike FPC, connectors cannot be mounted on FFC. FFC can only be used for simple parallel connections but is inexpensive.

FFC Connector and FFC

Coaxial Connector

This connector type is used mainly in analog antenna signals. It is also used to connect your TV. Coaxial connectors include those made by "machining" and those made by "press fitting". Other types include cold heading and metal die-cast connectors.

Machining Type

Machining Type Ex: 75 Ω Connector for Broadcasting

Broadcasting Equipment
Press Fit Type

Press Fit Type Ex: 50Ω Connector for Mobile Applications

Coaxial Cable

A coaxial cable is required to connect the coaxial connector. As shown in the picture, coaxial cables consist of a circular inner conductor and outer conductor. The signal flows through the internal conductor, but as frequency gets higher, signal try to escape from the internal conductor. If signal leaks out, the correct signal may be attenuated or become "noise" that adversely affects other signals. The outer conductor prevents signal leakage.

Coaxial Cable Design

Optical Connector

Optical Fiber

This final section covers optical fibers, which connect to optical connectors. Optical fiber usage stretches across the globe, including submarine cables. They are also distributed around your home. The role of the optical connector is to align the end faces of the optical fiber with each other without any gap or deviation in order to accurately transmit the flashing optical signal.
There are also passive type connector modules that transmit optical signal directly, and active type connector modules that convert electrical signals to optical signals and then convert the optical signal back to electrical signals.
Optical fiber transmission provides stable high speed transmission over long distances and is not affected by noise. It is also used in many places where you want electrical isolation. However, optical fibers are made of glass and easy to break, so cannot be bent at an acute angle.


Passive Type

Passive Type

Active Type

Active Type

Optical Connector Design

In the next article, we will explain connector naming and the corresponding features.

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