The DC line terminal (DC plug/ DC interface) is the core connection component between the power adapter and the electrical equipment. In products such as routers, surveillance cameras, LED lighting, notebook computers, and industrial control equipment, DC interfaces have a wide range of size and similar specifications. Wrong selection can easily lead to inoperability, poor contact, or even damage to the equipment.
This article collates the most complete DC line terminal models on the market and clearly classifies them according to specifications, current, polarity, and application scenarios, so that you can quickly identify, correctly select, and safely replace them.
（1） Basic knowledge of DC interface
1. Specifications: outer diameter (OD) × inner diameter (ID), in mm (such as 5.5×2.1mm).
2. Polarity: The vast majority of equipment is positive inside and negative outside (center +, shell-), and replacements must be consistent.
3. Current carrying: The larger the interface, the higher the current allowed. Small interfaces are used for small power devices, and large interfaces must be used for high-power devices.
4. Replacement principle: Same size, same polarity, same voltage, current ≥ original.
（2） General consumer electronics DC round port model (most commonly used)
Suitable for monitoring, routers, light cats, LED lights, set-top boxes, slightly, small appliances, etc.
DC interface model rated current common voltage typical application
2.35×0.7mm ≤1A 3V–5V Micro headphones, mini toys, small sensors
3.0×1.0mm ≤1.5A 5V–9V Old MP3, small fan, portable slightly
3.4×1.3mm ≤2A 5V–12V Mini camera, maker module, small motor
3.5×1.35mm ≤2A 5V–12V Voice recorder, camera, small instrument
4.0×1.7mm ≤3A 9V–12V Router, portable DVD, mini display
4.75×1.7mm ≤3A 12V Old set-top boxes, car accessories, printers
5.5×2.1mm ≤5A 12V Monitoring, router, LED light strip, light cat [Globally common]
5.5×2.5mm ≤5A 12V–24V Display, industrial control board, high-power LED
6.3×3.0mm ≤8A 24V Industrial controllers, broadcasting equipment, high-power monitoring
6.5×4.3mm ≤10A 24V–48V Industrial power supply, large LED modules, industrial control equipment
(3) Dedicated DC interface model for notebook computers (all brands)
The notebook DC interface has high precision and is not common to different brands. The following is the most complete model comparison table.
DC interface model rated current common voltage Applicable brands/models
4.0×1.35mm ≤3A 19V–20V Lenovo Xiaoxin, Asus Thin and Thin Book, Dell Lingyue
4.5×3.0mm ≤4.7A 19.5V Dell XPS, Latitude, HP vs. 66
4.8×1.7mm ≤3.5A 19V HP EliteBook, Asus Fearless
5.5×2.5mm ≤6A 19V–20V Lenovo old game book, Shenzhou, Asus game book
6.0×4.4mm ≤8A 19.5V Sony, Toshiba, Samsung old notebooks
7.4×5.0mm ≤10A 19.5V Dell Workstation, HP Shadow Elf
7.9×5.5mm ≤12A 19V–20V Lenovo Savior, ROG, MSI
8.0×5.5mm ≤15A 20V Alien, flagship game book
(4) Industry standard DC interface model
Industrial equipment uses a more stable, drop-proof and waterproof standard DC interface:
1. EIAJ standard (color circle distinguishes voltage)
EIAJ-1: 4.0×1.7mm (yellow ring) ≤6.5V
EIAJ-2: 4.8×1.7mm (red ring) 6.5 – 13.5V
EIAJ-3: 5.5×2.5mm (orange ring) 13.5 – 18V
EIAJ-4: 6.3×3.0mm (blue ring) 18 – 24V
EIAJ-5: 6.5×4.3mm (green ring) 24 – 48V
2.Locking/waterproof DC interface
Threaded latch DC: anti-falling, used on vehicle-mounted and mobile equipment
Waterproof DC interface (IP65/IP68): outdoor monitoring, garden equipment, industrial equipment
3. High-current industrial connector
Anderson plugs, MC4, XLR 4 pins, etc., used for energy storage, photovoltaic, broadcast equipment.
(5) Special DC interface (commonly used in modern equipment)
USB to DC: USB-A / Type-C to DC, supporting 5V, 9V, 12V, 19V, 20V Type-C PD to DC: Can replace notebook power supply and adapt to multiple DC interfaces On-board pin/cold pressure terminals: used for internal power supply of PCB and equipment assembly
(6) Five-step judgment method for DC interface selection (the most practical)
Measurement size: Outer diameter × inner diameter must be consistent Look at the polarity: positive inside and negative outside (the vast majority) Voltage: Must be consistent with the equipment Distribution current: power supply current ≥ equipment current Selected scenarios: waterproof for outdoor, lock-up for car, large interface for high power
(7) Summary
There are more than 30 common models of power adapter DC line terminals, mainly divided into:
There are four categories: general consumer, notebook, industrial standards, and special interfaces. Among them, 5.5×2.1mm and 5.5×2.5mm are the most common DC interfaces in the world;
4.0×1.35mm and 4.5×3.0mm are the mainstream of thin and light books; 7.9×5.5mm is dedicated to high-performance game books.
Correct selection of DC line terminals can ensure stable, safe and long-term use of the equipment.
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