An AC adapter is an external power supply that uses a rectifier to convert AC current to DC, and a transformer to convert voltage from 120 down to whatever is required. It consists of a power supply and a wire connecting it to the wall socket and to the electronic device. It regulates amperes, polarity, and plug size to conform to the electronic device. It is used to replace the function of batteries in laptops, portable music players, portable video players, and other portable and semi-portable devices.
Types of AC Adapters
Kinds of AC Adapters include the following:
An OEM AC adapter is made and distributed (or outsourced) by the manufacturer of a specific electronic device.
It is brand and model specific.
It assures the compatibility of the adapter to the device.
An after-market AC adapter designed with a specific voltage and ampere can only be used with a device with the same specifications.
It is generally cheaper than an OEM adapter.
Universal AC adapter
A universal AC adapter has adjustable volts, polarities, and amperes.
It can be used in different electronic devices with different requirements and specifications.
Choosing AC Adapters (Buying tips)
Specifications: If you plan to buy after-market, choose an AC adapter with the same electronic specifications as your old one. Make sure its plug size is compatible with the device you plan to use it with. To be sure, bring your device with you before you buy.
Volts and milliamps: When replacing your old AC adapter, look for one that matches the volts and milliamps of your old one. This information should be printed on the original adapter.