30VDC 800mA Universal Ac Dc Power Supply EU Plug Efficiency Level VI

Select an AC adapter and device with matching specifications
The right AC adapter for your device should have matching electrical ratings. The input voltage and current of the device must match the output voltage and current of the adapter. Check the device's product label or owner's manual for its rated voltage and current. Consumers who are learning how to choose an AC adapter should know that the output DC voltage of most power adapters is below 20V, while the input AC voltage is above 100V.

Selecting an adapter with a higher or lower voltage or current rating may cause the connected device to malfunction. This can happen if the VDC of the adapter is lower than the input voltage of the device, even though they are rated for the same current. Using a higher voltage adapter can cause connected equipment to detect overvoltage. An AC adapter that draws power at a higher voltage than required can cause connected devices to run hotter. Sending power at a higher voltage also shortens the life of the device and can burn out its internal circuitry.

Using an AC adapter with a different current rating may cause problems. When considering how to choose an AC adapter, avoid choosing one that draws less current than your device requires. Even if the adapter and device are rated for the same voltage, the device will try to draw more current than the AC adapter can handle. This can cause the adapter to overheat. The device might not turn on or have difficulty staying on. If the current is too low, the electronics may continue to function, but its battery will not charge.

You might be surprised that you can use an adapter with a higher current rating than your device. This recommendation applies as long as both devices have the same voltage rating. For example, a 10V/8A adapter can safely power a 10V/5A device.

The last thing to consider when researching how to choose the right power adapter is polarity. The polarity of the AC adapter connector must match the polarity of the power input or charging port on the device. There are two types of connector polarity: center positive and center negative. It's worth noting in the AC adapter buying guide that most power adapters use the center positive connector.