What is a DC plug?

This page explains the types, shapes, selection methods, and sizes of DC plugs in AC/DC power adapters — desktop & wall-mount.

What Types of DC Plugs Are There?

There are various DC plug standards, and when using an AC adapter with a device, it is necessary to select the correct plug.

• EIAJ Standard (EIAJ-1, EIAJ-2, EIAJ-3, EIAJ-4, EIAJ-5)
• 3-pin and 4-pin DIN plugs
• MINI USB
• MICRO USB
• Type-C

When choosing a DC plug, it is important to carefully check the shape and size.

Check the plug sizes using Unifive's compatible plug list

How to Choose the Correct DC Plug

Step 1: Confirm Connector Polarity

First, check the polarity of the connector. Generally, devices have connectors where one electrode is inside and the other is outside the cylindrical hole.

The most common type is center-positive, where the positive electrode connects to the center pin. The type where the negative electrode connects to the center pin is called center-negative.

If connected incorrectly, it can cause device failure, so caution is needed.

Check the Shape of the DC Plug

There are two main types of DC plug shapes.

They are called straight type and L-shaped type.

Check the Size of the DC Plug

To understand the size of a DC plug, you need to know the outer diameter, inner diameter, and plug length.

• Outer diameter: refers to the external diameter of the cylindrical part of the plug
• Inner diameter: refers to the internal diameter of the cylindrical part of the plug
• Plug length: refers to the length of the metal part. If it is too short relative to the depth of the socket, the metal part will not reach, and no electricity will be transmitted.

When measuring, you need to measure the diameter of the center pin and the inside of the port.

You must choose the right size plug because the inner and outer diameters of both male and female connectors must match to connect properly.

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