Standard Size Guide for DC Power Jack, 5.5*2.1 vs 5.5*2.5 vs 3.5*1.3mm

Compare the most common barrel dimensions of DC power jack, explain application differences of 5.5*2.1,5.5*2.5 and 3.5*1.3mm specifications to prevent connector mismatch.

5.5*2.1mm and 5.5*2.5mm are the two most widely used sizes of DC power jack. 5.5 means the outer barrel diameter, while 2.1 or 2.5 stands for inner pin diameter. The 5.5*2.1mm DC power jack fits most routers, LED power adapters and small home appliances. 5.5*2.5mm DC power jack is used for devices with higher current demand. 3.5*1.3mm DC power jack is a smaller size, reserved for mini portable electronics such as small sensors and handheld controllers. Size mismatch is a common mistake in product development. A 5.5*2.1 plug cannot work stably with 5.5*2.5 DC power jack, which will cause loose connection, intermittent power supply and heat generation. Engineers should confirm the barrel size of DC power jack at the early design stage and match corresponding DC plugs.