Before you buy an AC DC wall adapter, it's important to understand its power supply, output voltage, current, and polarity. When using a standard adapter, the positive plug must be inserted into the negative receptacle and vice versa. It's also important to understand that direct current is one-way. So, while voltage and current are equal, wattage does not tell you if the adapter will work for your device.
Power Supply for Wall Adapters
The power supply for AC DC wall adapters should not exceed its maximum output current because a device that draws too much current can fail. Overloading the converter will result in overheating and damage to the load. The power supply should have a load regulation feature of at least 0.1 millivolts. When it fails to do so, the power supply will shut down. This feature is an important feature to check for before buying.
Listed below are different types of AC DC wall adapters. They are commonly referred to as wall warts and AC DC adapters. These devices are typically housed in a plastic enclosure and come with a fixed input connector for direct connection to the wall. Some types have interchangeable input plugs. Make sure to check the plug types to be sure the device you plan to use is compatible with the type of power supply.
Output Voltage of AC DC Wall Adapters
Output voltage of AC DC wall adapters can be controlled through a variety of different methods. Some AC/DC wall adapters are automatic, stepping down the raw 115/230 Vac line voltage to a lower dc output that is compatible with the device or another power supply input. Some of the more popular models offer interchangeable tips, which means that the power supplied by the universal adapter can be controlled via a variety of methods. Universal adapters support 12 V DC vehicle supplies.
The output voltage of AC DC wall adapters is usually indicated on the brick part of the device. This output voltage should match the current in the device. If the adapter does not match the current of your device, it will likely shut down. The resulting damage may be instant, however. You should also pay attention to polarity. The lower voltage AC adapter may be the best option for your needs. If the voltage of the DC wall adapter matches the voltage of your device, you are set.
Current
When purchasing a wall adapter, it is important to select one with a high enough current rating to properly charge your devices. If your wall adapter does not have the correct current, your devices will not fully charge and may take longer than necessary to complete the process. Some wall adapters are interchangeable and are made with interchangeable AC input connectors. These are especially useful if you travel and will need to use one adapter in several countries.
A common AC DC power adapter will be labeled with an AC and DC symbol. These devices are essentially made up of a power transformer and rectifier circuit. Both types are compatible with a variety of electrical devices. AC and DC wall adapters are the same, but the two types of adapters may have slightly different characteristics. Some AC/DC adapters are designed for use with only one wall outlet, while others are made to function on more than one outlet.
Polarity of AC DC Wall Adapter
You can tell whether an AC DC wall adapter is polarized by the polarity symbols it displays. These symbols are commonly found on devices that use direct current (DC) or alternating current (AC) power. The adapter supplies power through a thin electrical cord terminating in a coaxial power connector. A barrel plug is one type of coaxial connector. To use it, you must match the polarity of the plug and cord with the device you want to charge. The positive plug contact should mate with the negative receptacle contact.
When looking for a new AC DC wall adapter, make sure you know its polarity. Most devices display the A, mAh, and Watts on their labels. The positive connector will usually have a center positive (+) receptacle, while the negative receptacle will have a center negative (-) connector. The two measurements you need to know are the voltage and current of the device you want to charge, and the polarity of the AC DC wall adapter.